Seagrasses from the Philippines 

SMITHSOI RIBUTIONS TO THE MARINE SCIENCES NUMBER 21 
SERIES PUBLICATIONS OF THE SMITHSONIAN INSTITUTION 

Emphasis upon publication as a means of "diffusing knowledge" was expressed 

by the first Secretary of the Smithsonian. In his formal plan for the Institution, Joseph 

Henry outlined a program that included the following statement: "It is proposed to 

publish a series of reports, giving an account of the new discoveries in science, and 

of the changes made from year to year in all branches of knowledge." This theme 

of basic research has been adhered to through the years by thousands of titles issued 

in series publications under the Smithsonian imprint, commencing with Smithsonian 

Contributions to Know/edge in 1848 and continuing with the following active series: 

Smithsonian Contributions to Anthropology 

Smithsonian Contributions to Astrophysics 

Smithsonian Contributions to Botany 

Smithsonian Contributions to the Earth Sciences 

Smithsonian Contributions to the Marine Sciences 

Smithsonian Contributions to Paleobiology 

Smithsonian Contributions to Zoo/ogy 

Smithsonian Studies in Air and Space 

Smithsonian Studies in History and Technology 

In these series, the Institution publishes small papers and full-scale monographs 

that report the research and collections of its various museums and bureaux or of 

professional colleagues in the world of science and scholarship. The publications are 

distributed by mailing lists to libraries, universities, and similar institutions throughout 

the world. 

Papers or monographs submitted for series publication are received by the 

Smithsonian Institution Press, subject to its own review for format and style, only 

through departments of the various Smithsonian museums or bureaux, where the 

manuscripts are given substantive review. Press requirements for manuscript and art 

preparation are outlined on the inside back cover. 

S. Dillon Ripley 

Secretary 

Smithsonian Institution 
SMITHSONIA N CONTRIBUTION S T O TH E MARIN E SCIENCE S •NUMBE R 21 

Seagrasses from the Philippines 

Ernani G. Mefiez, Ronald C. Phillips, 

and Hilconida P. Calumpong 

ISSUED 

DEC 11983 

SMITHSONIAN PUBLICATIONS 

SMITHSONIAN INSTITUTION PRESS 

City of Washington 

1983 
ABSTRAC T 

Menez, Ernani G., Ronald C. Phillips, and Hilconida P. Calumpong. Seagrasses from the Philippines. Smithsonian Contributions to the Marine Sciences, 

number 21, 40 pages, 26 figures, 1983.—Seagrasses were collected from various 

islands in the Philippines during 1978-1982. A total of 12 species in seven 

genera are recorded. Generic and specific keys, based on vegetative characters, 

are provided for easier differentiation of the seagrasses. General discussions of 

seagrass biology, ecology, collection and preservation are presented. Local and 

world distribution of Philippine seagrasses are also included. 

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded 

in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Seascape along the 

Atlantic coast of eastern North America. 

Library of Congress Cataloging in Publication Data 

Menez, Ernani G. 

Seagrasses from the Philippines. 

(Smithsonian contributions to the marine sciences ; no. 21) 

Bibliography: p. 

Supt. of Docs, no.: SI 1.41:21 

1. Seagrasses—Philippines. I. Phillipps, Ronald C. II. Calumpong, Hilconida P. III. Title. IV. Series. 

QK495.A14M46 1983 584.73 83-600168 
Contents 

Page 

Introduction 1 

Acknowledgments 3 

Materials and Methods 3 

Collecting and Preserving Seagrasses 4 

General Features of Seagrass Biology and Ecology 6 

Key to the Philippine Seagrasses 7 

Division ANTHOPHYTA 8 

Class MONOCOTYLEDONEAE 8 

Order HELOBIAE 8 

Family POTAMOGETONACEAE 8 

Cymodocea rotundata Ehrenberg and Hemprich, ex Ascherson 8 

Cymodocea serrulata (R. Brown) Ascherson and Magnus 8 

Halodule pinifolia (Miki) den Hartog 13 

Halodule uninervis (Forskal) Ascherson 13 

Syringodium isoetifolium (Ascherson) Dandy 18 

Thalassodendron ciliatum (Forskal) den Hartog 18 

Family HYDROCHARITACEAE 23 

Enhalus acoroides (L. f.) Royle 23 

Halophila beccarii Ascherson 24 

Halophila minor (Zollinger) den Hartog 26 

Halophila ovalis (R. Brown) Hooker f. 30 

Halophila spinulosa (R. Brown) Ascherson 33 

Thalassia hemprichii (Ehrenberg) Ascherson 33 

Literature Cited 39 

in 

Seagrasses from the Philippines 

Ernani G Menez, Ronald C. Phillips 

and Hilconida P. Calumpong 

Introduction 

T h e seagrass flora of the western tropical Pacific is unusually diverse (den Hartog, 1970). 

Tsuda, Fosberg, and Sachet (1977) reported ten 

species for Micronesia; Johnstone (1979) listed 13 

taxa for Papua New Guinea; and den Hartog 

(1970) reported 11 species for the Phillipines. 

Despite the interesting questions associated with 

this diversity and the widespread occurrence of 

seagrasses in the Philippines, only a few papers 

have been published which treat Philippine seagrasses. Earlier records include Blanco's (1837, 

1845, 1879) reports of Vallisneria sphaerocarpa ( = 

Enhalus acoroides) from Zambales. Another report 

of Vallisneria sphaerocarpa from Palawan was by 

Merrill (1918). Ostenfeld (1909) recorded Halophila ovata (= Halophila minor) from the Philippines, based on Loher's specimen from Luzon 

and later, Merrill's collection from Manila Bay. 

A critical morphological study of Thalassia hemprichii was published by Pascasio and Santos 

(1930). Domantay (1962) listed eight species of 

seagrasses in his study of the marine vegetation 

of the Hundred Islands in Pangasinan. Merrill 

(1912, 1915, 1918, 1925), Mendoza and del Rosario (1967) included seagrasses in vascular plant 

floras. Calumpong (1979) reported three seaEmani G. Menez, Smithsonian Oceanographic Sorting Center, National Museum of Natural History, Smithsonian Institution, Washington, D.C. 20560. Ronald C. Phillips, School of Natural and 

Mathematical Sciences, Seattle Pacific University, Seattle, Washington, 98119. Hilconida P. Calumpong, Department of Biology, Silliman University, Dumaguete City, Negros Oriental 6501, Philippines. 

grasses in an ecological study of the sea hare, 

Dolabella auricularia (Lightfoot), in Central Visayas region. Cordero (1981) illustrated and described the morphology and distribution of three 

species of seagrasses. 

T he Philippines is an archipelago of about 

7,100 islands. It lies between latitudes 4°40'-

21°50' N and longitudes 116°50'-126°35' E, surrounded by the South China Sea in the west, 

Sulu Sea and Celebes Sea in the south, the Philippine Sea, which opens into the Pacific Ocean, 

in the east, and the Luzon Strait in the north. 

T he country is naturally divided into four geographical regions (Figure 1): the Luzon Region, 

including the islands of Luzon, Babuyan, Catanduanes, Mindoro, Masbate, Romblon, and Marinduque; the Mindanao region, including Mindanao, Basilan, and the Sulu Group; the Visayas 

region, including Samar, Leyte, Bohol, Cebu, 

Negros, and Panay; and the Palawan region, 

including Palawan, Balabac, Culion, and the 

Cuyo Group. 

Seagrasses are important, but their role has 

often been overlooked due largely to their submerged state. Thayer, Wolfe, and Williams 

(1975) gave an overall summary of the importance of seagrasses: 

1. Seagrass has a high growth rate, producing an 

average of about 300-600 g dry weight/m2/ 

year, not including root production. Compared to world averages for cultivated corn 

(412 g C/m2) or rice (497 g C/m2), seagrass 

beds are more productive. 

1 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

1 2 0 1 2 4 

o Babuyan 

o o 

Catanduane s 

PALAWAN 

REGION 

16 

VISAYAS 

REGION 

12 

Dinaga t 

VSiargao 

MINDANAO 

REGION 

„' \9' ^•'Basila n 

a. <*r '• 

Tawi-Taw i 

, *\ 

FIGURE 1.—General map of the Philippines. 
NUMBER 21 

2. The leaves support a large number of epiphytic organisms, with a total biomass perhaps 

approaching that of the seagrass itself. 

3. Although a few organisms may feed directly 

on the seagrass and several may graze on the 

epiphytes, the major food chains are based on 

seagrass detritus and its resident microbes. 

4. The organic matter in the detritus and in 

decaying roots initiates sulfate reduction and 

maintains an active sulfur cycle. 

5. Seagrass roots bind the sediment together and, 

with the protection afforded by the leaves, 

surface erosion is reduced, thereby preserving 

the microbial flora of the sediment and the 

sediment-water interface. 

6. Seagrass leaves retard the currents and increase sedimentation of organic and inorganic 

materials around the plants. 

7. Seagrass absorbs phosphorus through the roots 

and the leaves; it may be that the phosphorus 

absorbed through the roots is released through 

the leaves, thereby returning phosphate from 

sediments to the water column. Nitrogen also 

is taken up by the roots and transferred to the 

leaves and into the medium. 

It is now imperative that we properly recognize 

how they contribute to the oceanic realm of the 

Philippines. All over the world humans and seagrasses are coming into conflict for space along 

the coast in areas that are in demand for human 

activities, from the creation of recreational places, 

such as marinas, to industrial ones, such as power 

plants, mining sites, freighter and tanker terminals. Unfortunately, discharges of warm water 

from power plants and silt and nutrients from 

mining, sewage treatment plants, and tanker terminals directly harm seagrasses. Before we destroy or even degrade any more seagrass habitats, 

we must know where the seagrasses are and the 

true value of this coastal resource. 

The resolution of this conflict need not be an 

inevitable loss of seagrasses. It is our hope that 

this study not only will alert people to the seagrasses by allowing them to identify the various 

species, but also by making them aware of where 

to find them and to appreciate some of the plant 

and animal associations that occur within the 

seagrass ecosystems. Most importantly, seagrass 

communities in the Philippines serve as habitats 

and breeding grounds for various marine organisms that are economically important to the 

local populace. Appropriate planning and reasonable environmental management can ensure the 

perpetuation of these ecosystems. 

ACKNOWLEDGMENTS.—We wish to thank Dr. 

Angel Alcala, Acting President, Silliman University, for allowing us to use the SU Marine Laboratory for our work and for providing accommodations. We appreciate the local transportation 

and accommodations provided by the University 

of San Carlos, through Prof. Cristobal Plateros, 

Chairman, Department of Biology. 

Hilconida Calumpong acknowledges the assistance of Mr. Willy Rasay and Ms. Janet Estacion 

in collecting and preparation of herbarium specimens of seagrasses. Ronald Phillips appreciates 

the financial aid, given by the Seattle Pacific 

University Institute for Research, for travel in 

March 1982. A portion of this research was supported by the National Science Foundation, 

International Decade of Ocean Exploration, Living Resources Program, Seagrass Ecosystem 

Study (OCE77-25559). Ernani Menez appreciates the travel and research support in the Philippines from the Smithsonian Institution Fluid 

Research Fund. 

For their critical review of this paper, we are 

indebted to Dr. Raymond Fosberg, Botanist 

Emeritus, Smithsonian Institution, to Dr. C. den 

Hartog, Catholic University, Nijmegen, The 

Netherlands, and to Dr. Calvin McMillan, Professor of Botany, University of Texas at Austin. 

The loan of Halophila beccarii and H. spinulosa 

specimens from Rijksherbarium, Leiden, is gratefully acknowledged. 

MATERIALS AND METHODS.—The seagrasses collected during the Smithsonian Institution Biological Expeditions of 1978 and 1979 to Central 

Visayas, Philippines, and the authors' personal 

collections during 1980-1982 from the Visayas 

region, Palawan, La Union, and Ilocos Norte, 

Philippines, were used in this study. Replicates of 

material are being deposited in the U.S. National 

Herbarium (Smithsonian Institution), the Seattle 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

Pacific University Herbarium, the Silliman University Herbarium, the National Herbarium of 

the Philippines, and the Rijksherbarium. 

In the systematic section of this paper, the 

author, date, and page of the original publication 

of each taxon, plus basionyms and published 

records from the Philippines, are given. Th e characteristics, natural history, local and world distribution of each species are also given. A dichotomous key and line drawings are included in order 

to facilitate easier identification of the twelve 

species of seagrasses from the Philippines. Most 

of the natural history and distribution data of 

Philippine seagrasses in this study are from den 

Hartog's (1964, 1970) publications. Additional 

information has been taken from Isaac (1968), 

Kay (1971), Kirkman (1975), McMillan (1980a, 

b), McMillan, Bridges, Kock, and Falanruw 

(1982) and Johnstone (1982). 

COLLECTING AND PRESERVING SEAGRASSES.— 

Seagrasses may be collected as drift plants cast 

ashore or as freshly dug specimens. The major 

problems in the use of drift plants is that they 

may be broken and their original attachment site 

is uncertain. It is known that seagrass plants are 

buoyant and can float for weeks if detached from 

the bottom. 

T he recommended procedure for collecting 

and preserving seagrass specimens for herbarium 

storage and study is as follows. A collector should 

get the entire plant including the root and rhizome system. One should use a shovel or dig by 

hand deeply enough into the substrate to get 

below the rhizome mat. The plant mass can then 

be torn loose from the bottom. All sediment and 

animals should be washed from the rhizome and 

roots. Specimens covering all development phases 

should be collected from the same area. It is best 

to include plants with flowers, fruits, and seeds, 

as well as vegetative plants with intact leaf tips 

and root systems. 

T he plants should be returned to the laboratory 

in a plastic bag, preferably in an ice chest. The 

plants should be kept moist and should not be 

exposed to direct sunlight. 

T he plants can be preserved by dry-mounting 

on herbarium paper or by soaking first in a 

solution of seawater formalin. Soaking the plants 

first in formalin keeps down the growth of fungi 

(mildew) and destruction by insects, but renders 

the plants useless for chemical analysis. If one 

wishes to kill the plants before mounting on 

herbarium paper, the plants should be soaked for 

one hour in a 5% solution of seawater-formalin 

(8 parts seawater to 1 part formaldehyde). The n 

the plants should be drained dry and mounted 

on herbarium sheets or other stiff, high-quality 

paper. 

Seagrasses, such as the small and fragile Halophila species, are most easily mounted on herbarium sheets if they are floated first in a tray of 

seawater. A sheet of herbarium paper is placed 

under the plant in the water, the plant arranged 

on the sheet, the sheet is lifted out and the excess 

water drained off. Th e sheet is then ready for the 

plant press (Figure 2). 

The plant press can be made from two pieces 

of 3/8-inch plywood, each 12 X 17 inches. Inside 

the press there should be a complement of corrugated cardboard ventilators, heavy blotters, 

and waxed paper, in addition to the herbarium 

paper with the specimens. Each of these sheets is 

the same size as the plant press. Two or more 

straps (belts or pieces of clothesline) are needed 

to hold the press together. 

T h e plant press is assembled by placing a 

herbarium sheet with its plant specimen on a 

blotter. A sheet of waxed paper is placed on top 

of the specimen. Another blotter is placed on top 

of the waxed paper. Cardboard ventilators are 

used to separate blotters. When all of the plants 

have been put into the press, the straps are used 

to bind the press tightly together. Th e press may 

be placed over a source of mild heat to allow a 

current of warm dry air to rise through the corrugations of the ventilators. Until the plants are 

dry, the press should be opened each day and dry 

ventilators and blotters exchanged for the wet 

ones. When the sheets are dry, the dried plants 

should be fixed to the herbarium sheets using 

clear Duco cement. 

T he following information should be typed on 

a specimen-label form: scientific name (with author), habitat information (depth of water, type 
NUMBER 21 

Genus/Species 

Habitat Data: 

Locati on: 

Date: 

Collector: 

Full Plant Press 

Herbarium Sheet with Data 

{•>S/S//'>->f/'//Sf / / f f ^ZZ 

S S S SSSSSSSSS 5 ^^\\\\^^i 

C 

Plywood 

Cardboard Ventilator 

Blotter 

Waxed Paper 

Herbarium Sheet with Specimen 

Blotter 

Cardboard Ventilator 

P lywood 

Plant Press Arrangement 

FIGURE 2.—Illustration showing proper plant press arrangement for drying seagrasses. 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

of substrate, etc.), location (specific but also general area), date of collection, collector's name. 

The label should be pasted in the lower right 

corner of the sheet. 

General Features of Seagrass Biology and 

Ecology 

The narrow fringe of the edge of the sea is both 

the most productive and the most threatened 

portion of the ocean. In this area of the shallow 

water light can penetrate to the bottom and 

nutrients arrive from both land and sea. It is here 

that marine plant ecosystems flourish. These marine systems are the foundations of inshore productivity and form the basis for animal life. 

The value and significance of the shallow-water 

habitats have been overlooked in the past, in part 

because the connections from the plants to animals are complex and often indirect. Paradoxically, the most important contribution of all seagrass ecosystems to the chains of life is death. The 

bacteria that devour the dead leaves of the plant 

not only nourish and enrich the area in which the 

plants grow, but also affect waters for miles 

around. Seagrass and mangrove leaves have been 

found in deep-sea trenches far from shore and 

thousands of feet deep. Even in these most remote 

regions of the sea, the leaves provide food and 

shelter for resident animals. 

Seagrasses are not true grasses, but they do 

resemble them and have many similarities with 

them in the biology of their life cycle. Seagrasses 

usually form dense meadows that resemble more 

familiar prairies or grasslands. Seagrasses are vascular plants. The vascular system in the seagrasses 

consists of an internal network of tubes that is 

continuous from the roots to the leaf tips, transporting water, nutrients, and gases for tissue 

growth. Because of this system, seagrass growing 

in sand or mud can use the highly concentrated 

nutrients of the bottom, nutrients that may be 

hundreds or thousands of times more concentrated than those in the overlying water column. 

This source, the bottom sediment, is unavailable 

to all other marine plants; these others must 

depend for growth only on nutrients dissolved in 

the water. Seagrasses can absorb nutrients from 

water through their leaves like algae, but are not 

limited to that source. Seagrasses, then, are a 

mechanism for returning nutrients to other marine life that would otherwise be lost in the sediments. They are the only plants in the sea that 

can do this. The significance of this dual nutrient 

source is reflected in growth rates that are high 

or higher than those of any other plant community in the sea. The roots and rhizomes not only 

absorb nutrients from the sediment, but also prevent the movement of bottom sediments. In dense 

meadows of Thalassia hemprichii (turtle grass) and 

Enhalus acoroides, the roots and rhizomes form a 

dense mat that prevents erosion of the coast that 

would otherwise occur from strong currents and 

severe typhoons. Since they occur inshore of the 

coral fore-reef, they act in concert with the reef in 

coastal protection. 

Part of the importance of seagrasses is their 

high productivity. Seagrass beds have been shown 

to be among the most productive areas of the 

earth, including those under intensive agriculture. Seagrasses have a complement of attached 

algae, called epiphytes, which contribute to the 

high productivity of the seagrass ecosystem. This 

primary productivity is the first link in the food 

chains of these ecosystems, and generally supports 

a high productivity in the associated animal community. 

Seagrasses constitute a haven and refuge for 

animals in the sea. They are especially important 

as nurseries for fish, shrimps, lobsters, scallops, 

and other valuable food animals. The protection 

that these plant systems afford extends beyond 

their associated animal life to the coast itself. 

Although many of the animal associations with 

seagrasses are indirect and inconspicuous, there 

are notable exceptions: dugongs, sea turtles, some 

fish, and sea urchins and other invertebrates feed 

directly on these plants. 

A seagrass meadow or bed may consist of a few 

hundred to a few thousand leafy shoots per square 

meter and can cover bottom areas from a few 

acres up to many square miles. These meadows 

are crucial habitats for a variety of marine life. 

To some animals they are a refuge; to others they 

are the local swim-in restaurant where a free 

lunch is always available. One of the reasons for 
NUMBER 21 

this concentration of marine life in seagrass 

meadows is the great habitat complexity resulting 

from the dense canopy of leaves; the leaves provide a surface area that can be 20 or more times 

greater than that of the bottom they occupy — a 

veritable jungle. A myriad of small animals and 

plants, some epiphytes and some merely clinging, 

can be found on seagrass leaves. These form an 

essential part of the complex food webs that exist 

in a seagrass meadow. 

An essential feature of any seagrass meadow is 

the fate of the leaves as they age and become 

detached from the leaf stalk, an event similar to 

the autumn drop of leaves in a forest. A large 

proportion of these leaves sink to the bottom 

where they become the basis of yet another complex food web. Through wave action and browsing activities of invertebrates, the leaves break 

down and decompose into particulate matter that 

remains suspended in the water column. In so 

doing, they provide inorganic nutrients that are 

essential to the continued growth of the living 

seagrasses, and nourishment to a variety of bacteria. Some of the soluble plant chemicals leach 

out into the surrounding water and help to feed 

the same bacteria. These bacteria are the food of 

diverse species of small animals that are themselves the food for slightly larger species of animals and so it goes. This decomposer food chain 

begins with bacteria in the upper levels of bottom 

sediments and around the surface of the particulate plant matter, an environment devoid of oxygen, but eventually it leads to the more familiar larger food animals, worms, clams, shrimps 

and consequently to fishes. The steps in this food 

chain are still more obscure than the one based 

on direct grazers and there is still doubt about its 

significance in the economy of the sea. The production of detritus from the constant sloughing 

of leaves in the seagrass meadow results in a 

relatively constant source of food for the bacteria 

and animals of the decomposer food chain 

throughout the year. 

Many studies in the United States have proven 

that seagrass presence and growth is absolutely 

dependent on relatively clear water. Seagrasses 

stabilize bottom sediments and baffle water motion inside the meadow, but additions of dirty 

water from dredging, mining, sewage, and boating activities can sharply curtail or eliminate the 

productivity or even presence of seagrass in an 

Key to the Philippine Seagrasses 

Leaves terete Syringodium isoetifolium 

Leaves flat 2 

Leaves elliptic, ovate, lanceolate or linear-oblong; 4—30 mm long 

Halophila 

A. Leaves lanceolate, without cross-veins H. beccarii 

Leaves otherwise, with cross-veins B 

B. Leaves with 12-22 pairs of cross-veins H. ovalis 

Leaves with 4-7 pairs of cross-veins C 

C. Leaves up to 22 pairs, distichous on long shoot H. spinulosa 

Leaves in pairs on every short shoot H. minor 

Leaves linear, usually 5-100 cm long 3 

Leaves ligulate 4 

Leaves not ligulate 6 

Nerves no more than 3 Halodule 

A. Leaf tip with irregular serrations; tip of midrib often furcate 

H. pinifolia 

Leaf tip tridentate; tip of midrib not furcate H. uninervis 

Nerves more than 3 5 
SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

5. Unbranched or once-branched shoots produced at every fourth internode 

on rhizome; leaf tips with bi- trifurcate teeth; roots borne on internode 

with numerous tough, wiry laterals; internodes 3-10 mm long 

Thalassodendron ciliatum 

Not as above Cymodocea 

A. Leaf tip smooth or slightly serrulate; leaf blades linear C. rotundata 

Leaf tip serrate-dentate; leaf blades linear-falcate C. serrulata 

6. Rhizome 2-4 mm in diameter; roots densely beset with filiform laterals; 

leaves linear-falcate; without basal black fibers .. Thalassia hemprichii 

Rhizome more than 1 cm in diameter; roots naked; leaves linear; with 

persistent basal black fibers Enhalus acoroides 

Division ANTHOPHYT A 

Class MONOCOTYLEDONEAE 

Order HELOBIAE 

Family POTAMOGETONACEA E 

Cymodocea rotundata Ehrenberg and 

Hemprich, ex Ascherson 

FIGURES 3A,B, 4 

Cymodocea rotundata Ehrenberg and Hemprich, ex Ascherson, 

187la:83.—Merrill, 1925:24.—Mendoza and del Rosario, 

1967:12.—den Hartog, 1970:166, fig. 47. 

CHARACTERISTICS.—Plants of moderate size, 

with moderately robust rhizomes, reaching 2 mm 

in diameter; internodes 0.5-3 cm long; laxly 

branched roots usually 1-3 per node. Erect shoots 

short, generally with 2-4 leaves. Persistent leaf 

sheaths up to 4 cm long, usually forming scarious 

mass at maturity; when shed, conspicuous scars 

are left on stem. Leaf blades linear, 2-4 mm wide 

and up to 10 cm long, with round apices or 

slightly serrulate, nerves 8-12. 

NATURAL HISTORY.—Cymodocea rotundata occurs 

in shallow water, on sand-mud or sand substrates 

in sheltered coves or bays, lagoons, mouth of 

rivers and coral reefs. Th e plant may be found 

growing with Halophila ovalis, Halodule uninervis, 

Enhalus acoroides, Thalassia hemprichii, Syringodium 

isoetifolium, or Cymodocea serrulata. Epiphytic algae 

found on leaves of the plant include melobesioids 

and Hypnea. In New Caledonia and Thursday 

Island, staminate flowers were observed during 

April and November, respectively. Pistillate flowers have been reported during November at 

Thursday Island. At Bristow Island, both staminate and pistillate flowers were found in March. 

Plants with fruits were recorded from Yap, 

Tomil-Gagil, and Ma p islands in Micronesia during March and June-July. In New Guinea and 

the island of Bali, fruits were observed in June . 

PHILIPPINE DISTRIBUTION.—Luzon (Lingayen 

Gulf, Catanduanes, Mindoro); Palawan (Cuyo 

Islands); Visayas (Samar, Negros, Siquijor); Mindanao (Pearl Bank, Tawi-Tawi Group). 

RANGE.—C. rotundata is widely distributed in 

the Indian and western Pacific oceans. It occurs 

in Egypt, Sudan, Kenya, Tanzania, Mozambique, Madagascar, Yemen, Thailand, Andaman 

Islands, Ryukyu Islands, Malaysia, Indonesia, 

Papua New Guinea, Caroline Islands, Queensland, and New Caledonia. 

Cymodocea serrulata (R. Brown) Ascherson 

and Magnus 

FIGURES 5A-C, 6 

Caulinia serrulata R. Brown, 1810:339. 

Cymodocea serrulata (R. Brown) Ascherson and Magnus, in 

Ascherson, 187la:84.—Merrill, 1925:24.—Mendoza and 

del Rosario, 1967:13.—den Hartog, 1970:171, fig. 48. 

CHARACTERISTICS.—Plants of moderate size, 

rhizomes 2-3 mm in diameter; internodes 1-4 cm 

long; usually 2 to several sparsely branched roots 

per node. Erect shoots short, bearing u p to 4 
NUMBER 21 

B 

FIGURE 3.—Cymodocea rotundata: A , habit of plant, X 1.4; B, upper portion of a leaf showing 

perpendicular veins, X 4.4. 
10 SMITHSONIAN CONTFIBUTIONS TO THE MARINE SCIENCES 

FIGURE 4.—Cymodocea rotundata: top, world distribution; bottom, Philippine distribution. 
NUMBER 21 11 

FIGURE 5.—Cymodocea serrulata: A, habit of plant, X 1.2; B, upper portion of a leaf showing 

serrate tip and perpendicular veins, X 2.2; c, fruit, X 1.8 
12 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 6.—Cymodocea serrulata: top, world distribution; bottom, Philippine distribution. 
NUMBER 21 13 

leaves. Leaf sheaths 1-3 cm long, tapered towards 

the base; when shed, leaving conspicuous scars 

around the stem. Leaf blades linear-falcate, 3-7 

mm wide, u p to 9 cm long, narrowed at the base; 

with round to obtuse, serrate leaf tips; margins 

mostly entire, spinulose only near the tip; having 

8-16 nerves connected by cross-veins. Fruits 

nearly elliptic, compressed, sessile and with dorsal 

ridges. 

NATURAL HISTORY.—Cymodocea serrulata occurs 

in the lower intertidal zone, in sheltered localities, 

on coarse coral-sand, sand-mud, or mud with 

coral rubble substrates. The plant is reported 

growing together with Thalassia hemprichii, Enhalus 

acoroides, Halophila ovalis, Halodule uninervis, and 

Syringodium isoetifolium. Pistillate flowers have been 

reported during April in New Caledonia; in 

Kenya, they have been observed in Januar y and 

August. Plants with staminate flowers have been 

recorded during February and March from Moreton Bay, Queensland. In Kenya, they occurred 

in September. Contrary to den Hartog's (1970) 

comment that Cymodocea serrulata is absent in 

places where there is freshwater influence, in 

Albay Gulf, southeastern Luzon, Philippines, the 

plant was collected from boulders near the mouth 

of a stream, growing together with Halodule uninervis. Epiphytic algae found on the leaves of 

Cymodocea serrulata were melobesioids, Ceramium 

and Acrochaetium. In Negros, Philippines, fruits 

were found on Cymodocea serrulata in August. 

PHILIPPINE DISTRIBUTION.—Luzon (Pangasinan, Albay, Catanduanes, Mindoro); Palawan 

(Bajallanura Island, Double Island); Visayas (Negros, Leyte); Mindanao (Zamboanga). 

RANGE.—C. serrulata is common in tropical and 

subtropical regions. It occurs in Egypt, Sudan, 

Kenya, Tanzania, Mozambique, Madagascar, 

Comoro Islands, Seychelles, Yemen, Sri Lanka, 

Malaysia, Indonesia, Western Australia, Queensland, Papua New Guinea, Caroline Islands, and 

New Caledonia. 

Halodule pinifolia (Miki) den Hartog 

FIGURES 7A,B, 8 

Diplanthera pinifolia Miki, 1932:787. 

Halodule pinifolia (Miki) den Hartog, 1964:309; 1970:158. 

CHARACTERISTICS.—Plants small, with slender 

rhizomes, up to 1.5 mm in diameter; internodes 

usually 0.5-2.0 cm long; simple or laxly branched 

roots, 2 to several per node. Short, erect shoots 

consisting of 2-4 leaves borne at each node. Leaf 

blades linear, 4-15 cm long, not more than 1.5 

mm wide. Leaf tips obtuse with few irregular 

serrations. Leaf margins entire; conspicuous midrib furcate at the tip. Basal portion of leaves 

enclosed by sheaths, 3 cm long. Ovate scales on 

each node not persistent at maturity. 

NATURAL HISTORY.—Halodule pinifolia occurs in 

sheltered and semi-exposed bays, coral reef platforms, in pools, also in wave-beaten sites. Th e 

plant has only been collected from two sites along 

the coast of Negros and Sama r islands of the 

Visayas region of the Philippines. Those collected 

from Negros were from the upper sublittoral zone 

and were sterile. The rarity of this species in our 

collections suggests that it is less tolerant of prevailing hydrographic parameters compared to 

other seagrasses. In the literature (den Hartog, 

1970), its companion species on compact mu d is 

Cymodocea rotundata and on soft mud, Halophila 

ovalis. At Cairns, Queensland, flowering and fruiting plants of Halodule pinifolia were found during 

November. Species of crustose melobesioids Acrochaetium, Ceramium, Hypnea, and Polysiphonia, were 

found growing on leaves of Halodule pinifolia. 

PHILIPPINE DISTRIBUTION.—Luzon (Mindoro); 

Visayas (Negros, Samar, Bohol); Mindano (Cavilli Island, Pearl Bank). 

RANGE.—H. pinifolia is most commonly distributed in tropical and subtropical localities. It occurs in Ryukyu Islands, Vietnam, Indonesia, 

Tonga Islands, Papua New Guinea, Fiji Islands, 

Queensland and New Caledonia. 

Halodule uninervis (Forskal) Ascherson 

FIGURES 9A,B, 10 

Zostera uninervis Forskal, 1775:157. 

Halodule uninervis (Forskal) Ascherson, in Boissier, 1882:24.— 

den Hartog, 1970:147. 

Diplanthera uninervis Ascherson, in Engler and Prantl, 

1897:37.—Domantay, 1962:275.—Mendoza and del Rosario, 1967:13. 

CHARACTERISTICS.—Plants of moderate size, 
14 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 7.—Halodule pinifolia: A, habit of plant, X 2.1; B, upper portion of leaf showing furcate 

midrib and irregular teeth at tip, X 28. 
NUMBER 21 15 

FIGURE 8.—Halodule pinifolia: top, world distribution; bottom, Philippine distribution. 
16 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 9.—Halodule uninervis: A, habit of plant, X 0.95; B, leaf tip showing two acuminate teeth 

and median nerve, X 10.4. 

with slender rhizomes barely reaching 2 mm in 

diameter; internodes 2-3 cm long; unbranched to 

sparsely branched roots not more than 5 per node. 

Erect shoots short, with 2-4 leaves enveloped 

below by a 1-2 cm long leaf sheath; when shed, 

leaf sheaths leave conspicuous annular scars on 

stem. Leaf blades linear and narrow at the base, 

2-5 mm wide, reaching 15 cm in length. Blades 
NUMBER 21 17 

FIGURE 10.—Halodule uninervis: top, world distribution; bottom, Philippine distribution. 
1 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

with 3 nerves; the middle one very distinct and 

ending in the median apical obtuse tooth, while 

the lateral nerves ending in 2 abruptly acuminate 

teeth. Leaf tip tridentate; leaf margin entire. 

NATURAL HISTORY.—Halodule uninervis occurs in 

sheltered or exposed localities in the shallow intertidal to the upper subtidal zone, on sand-mud, 

coarse coral-sand, or sand substrates. In the Philippines, occasional patches of the plant may be 

mixed with Thalassia hemprichii, Halophila ovalis, 

Syringodium isoetifolium, Enhalus acoroides, and Cymodocea serrulata. On the leaves and particularly 

the basal parts of Halodule univervis, epiphytic 

algae, such as Colpomenia sinuosa, Dictyopteris delicatula, Jania adherens, Mastophora rosea, and species 

of Ceramium, were found. Flowering and fruiting 

plants of Halodule uninervis have not been observed 

to date in the Philippines. At Queensland, flowering plants were found during October and November. 

PHILIPPIN E DISTRIBUTION.—Luzon (Manila 

Bay, Pangasinan, Albay, Catanduanes, Mindoro, 

La Union, Ilocos Norte); Palawan (Cuyo Islands); 

Visayas (Negros, Bohol, Leyte, Cebu); Mindano 

(Zamboanga). 

RANGE.—Halodule uninervis is widely distributed 

along the tropical coast of the Indian and western 

Pacific oceans. It occurs in Egypt, Eritrea, Somalia, Tanzania, Madagascar, Mozambique, 

Mauritius, Seychelles, Saudi Arabia, Kuwait, 

Bahrain Islands, Yemen, Sri Lanka, Andama n 

Islands, Thailand, Vietnam, Malaysia, Indonesia, 

Papua New Guinea, Western Australia, Queensland, New Caledonia, Tonga Islands, Caroline 

Islands, Mariana Islands, and Japan . 

Syringodium isoetifolium (Ascherson) Dandy 

FIGURES 11A-D, 12 

Cymodocea isoetifolia Ascherson, 1868:163. 

Syringodium isoetifolium (Ascherson) Dandy, in Dandy and 

Tandy, 1939:116.—den Hartog, 1970:177, figs. 50, 51a-d. 

CHARACTERISTICS.—Plants of moderate size, 

with slender rhizomes not more than 1.5 mm in 

diameter; internodes 3-15 mm long; one to several laxly branched roots below the erect shoots. 

Erect shoot consisting of 2-3 terete leaf blades per 

node. Leaf blades reaching 25 cm long, 1.0-2.5 

mm in diameter, narrow towards the base; central 

vascular bundle encircled by 6-11 air channels; 

pericentral vascular bundles 7-9. Leaf sheaths up 

to 5 cm long. Inflorescence cymose; sheaths of 

reduced leaves in the inflorescence mostly 4-7 

mm long. Staminate flowers with 2 ovate anthers, 

4 mm long and connected by the middle to the 

apex of a 2 mm, terete stalk. 

NATURAL HISTORY.—Syringodium isoetifolium occurs in sheltered and semi-exposed habitats, on 

coarse coral-sand substrate. The plants are found 

in the upper subtidal zone, forming thick carpets 

with Thalassia hemprichii, Cymodocea rotundata, C. 

serrulata, and Halodule uninervis. In the Philippines, 

pistillate and staminate flowers were found during May. Crustose melobesioids sometimes heavy 

on leaf blades; Chaetomorpha crassa, Tolypiocladia 

glomerulata, Hypnea valentiae, Dictyota species, and 

Gracilaria blodgettii attached at the base of leaves 

and on leaf sheaths of S. isoetifolium. 

PHILIPPINE DISTRIBUTION.—Luzon (Pangasinan, Albay, Catanduanes, Mindoro, La Union); 

Visayas (Negros, Siquijor, Bohol); Mindanao 

(Zamboanga). 

RANGE.—Syringodium isoetifolium is widely distributed in the tropics. It occurs in Egypt, Kenya, 

Tanzania, Mozambique, Madagascar, Seychelles, Mauritius, Yemen, Bahrain Islands, Sri 

Lanka, Nicobar Islands, Vietnam, Malaysia, 

Papua New Guinea, Tonga Islands, Caroline Islands, Ryukyu Islands, Western Australia, 

Queensland, and New Caledonia. 

Thalassodendron ciliatum (Forskal) den 

Hartog 

FIGURES 13A-C,14 

Zostera ciliata Forskal, 1775:157. 

Thalassodendron ciliatum (Forskal) den Hartog, 1970:186, figs. 

52a-j.—Menez and Calumpong, 1983:103-111. 

CHARACTERISTICS.—Plants moderately large, 

occasionally branched once, reaching a height of 

45 cm. Rhizome thick, u p to 5 mm in diameter; 

internodes 3-10 mm long; roots 1-6 borne on 
NUMBER 21 19 

FIGURE 11.—Syringodium isoetifolium: A, habit of plant, X 0.3; B, staminate flower with 

2 anthers, X 4.1; c, portion of male plant, X 3.1; D, section of leaf-blade showing 

central vascular bundle and air channels, X 21.8. 
20 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 12.—Syringodium isoetifolium: top, world distribution; bottom, Philippine distribution. 
NUMBER 21 21 

FIGURE 13.— Thalassodendron ciliatum: A, habit of plant, X 0.8; B, leaf with ligules and sheath, X 

1.9; c, details of apical portion of leaf showing denticulate tip, irregularly serrate margin and 

nerves connected by cross veins, X 6.3. 
22 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 14.— Thalassodendron ciliatum: top, world distribution; bottom, Philippine distribution. 
NUMBER 21 23 

internode, with tough, wiry laterals, no more than 

1.5 mm in diameter. Two stems produced at 

every fourth internode on rhizome; one fully developed, long and erect with numerous leaf scars 

and another, usually an undeveloped stem-bud. 

Uppe r part of erect stem compressed, but the 

basal portion terete. Leaf blades usually 6, linearfalcate, narrowed towards the base, u p to 10 mm 

wide and 13 cm long; leaf tips rounded, denticulate; apical teeth bi- trifurcate; upper half of 

leaf margin with irregular serrations, becoming 

distant and few towards the base; lower half of 

leaf margin almost entire. Leaf nerves 12-18, 

connected by a few oblique cross-veins. Leaf 

sheaths obtuse, u p to 12 mm wide and 20 mm 

long, with obtuse auriculae and ligules. 

NATURAL HISTORY.— Thalassodendron ciliatum occurs in sheltered and semi-exposed localities, in 

the upper sublittoral zone. The plants from the 

Philippines were sterile and found in small 

patches among dead and living corals in clear 

water. In Kenya and Mozambique, staminate 

and pistillate flowers were observed during August and January, respectively. In Tanzania, 

staminate flowers have been recorded during August. Algal epiphytes found growing on Philippine specimens of T. ciliatum include Hypnea valentiae, Jania adherens, Amphiroa rigida, Codium arabicum, Giffordia rallsiae, Sphacelaria furcigera, Polysiphonia mollis, species of Padina and Dictyota, Ceramium mazatlanense, and Champia parvula. The latter 

two algal taxa were present on both leaves and 

stems, while the rest were only on the stem. 

T he authors wish to point out that Thalassodendron ciliatum may often be confused with the "longstemmed" Cymodocea serrulata. Johnstone (1982) 

has found two growth forms of Cymodocea serrulata 

in New Guinea and reported that the "normal " 

form to be the most common. McMillan (1983) 

has found evidence that the "long-stemmed" 

plants are controlled by light intensity. T ciliatum 

and C. serrulata are easily distinguished by a careful morphological examination. 

PHILIPPINE DISTRIBUTION.—Palawan (Bajallanura Island, Tidepole Island, Double Island, western side of Tabo n Cave at Quezon). 

RANGE.— T ciliatum occurs in Egypt, Sudan, 

Somalia, Kenya, Tanzania, Mozambique, South 

Africa, Madagascar, Chagos Archipelago, Seychelles, Amirante Islands, Aldabra Islands, Comoro Island, Mauritius, Saudi Arabia, Iran, Indonesia, Papua New Guinea, Solomon Islands, Caroline Islands, and Queensland. 

Family HYDROCHARITACEAE 

Enhalus acoroides (L. f.) Royle 

FIGURE 15, 16 

Stratiotes acoroides L. f., 1781:268. 

Vallisneria sphaerocarpa Blanco, 1837:780; 1845:538; 1879: 

186.—Merrill, 1918:59. 

Enhalus acoroides (L. f.) Royle, 1840:453.—Merrill, 1925:27.— 

Domantay, 1962:275.—den Hartog, 1970:215, fig. 60.— 

Cordero, 1981:321, fig. 1. 

CHARACTERISTICS.—This is the largest of the 

seagrass species from the Philippines, reaching a 

height of more than a meter. Rhizome thick, up 

to 1.5 cm in diameter, deeply embedded in substrate, bearing many roots, 2-5 mm in diameter 

and up to 15 cm long. Persistent leaf fibers very 

dense and masking rhizome. Leaves 3 or 4, produced directly from rhizome; leaf blades linear, 

to 1.5 cm wide and reaching 1 m in length; leaf 

tips rounded, beset occasionally with minute serrate projections when young; leaf margins entire, 

slightly rolled. Characteristic tough, black vascular bundles persistent after death and decay of 

other leaf tissues. Nerves 10-40, parallel to about 

as many air-channels. Fruits ovoid, 4-7 cm long, 

with acuminate tips and densely covered with 

bifid projections. Fruit stalk long and coiled. 

NATURAL HISTORY.—Enhalus acoroides occurs in 

sheltered localities in the lower intertidal and 

upper subtidal zones, on sand-mud, coarse coralsand or mud substrates. In the Philippines, the 

plant was observed in pure stands next to a 

mangrove where silt was thick and water was 

murky, or in occasional patches in coarse coralsand growing together with Thalassia hemprichii, 

or mixed with Halodule uninervis, Cymodocea serrulata, Syringodium isoetifolium, and Halophila ovalis. 

Fruiting plants of Enhalus acoroides were found in 

May-Octobe r in Central Visayas and during 
24 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 15.—Enhalus acoroides: habit of plant, X 0.4. 

April staminate flowers were collected from 

southern Luzon in the Philippines. According to 

den Hartog (1970), this plant probably flowers 

and fruits the whole year round. Crustose melobesioids are sometimes very thick on leaves and 

on black "hairs." Hypnea and Cladophora were 

found attached to the melobesioids. Few thalli of 

Ceramium were epiphytic on Enhalus acoroides 

leaves. 

PHILIPPINE DISTRIBUTION.—Luzon (Zambales, 

Catanduanes, Mindoro); Palawan (Tay-tay Bay, 

Quezon, Cuyo Islands); Visayas (Cebu, Samar, 

Leyte, Negros, Bohol); Mindanao (Surigao, Zamboanga, Basilan). 

RANGE.—E. acoroides is widely distributed in 

the tropics. It occurs in Kenya, .Seychelles, Madagascar, Saudi Arabia, Yemen, India, Sri Lanka, 

Andaman Islands, Malaysia, Kampuchea , Vietnam, Ryukyu Islands, Indonesia, Papua New 

Guinea, Mariana Islands, Caroline Islands, 

Queensland, and New Caledonia. 

Halophila beccarii Ascherson 

FIGURES 17A,B, 18 

Halophila beccarii Ascherson, 1871b:302.—Merrill, 1912:70; 

1925:25.—Mendoza and del Rosario, 1967:21.—den Hartog, 1970:261. 

CHARACTERISTICS.—Plants small, with slender 

rhizomes not more than 1 mm in diameter; internodes 1-3 cm long; with one root at each node. 

Uneven pair of scales enveloping the erect shoot 

that consists of up to 10 closely set, petiolated 

leaves. Leaf blades lanceolate, with acute apices 

and cuneate or attenuate bases, 8-15 mm long 

and 1-2 mm wide; margins entire, rarely minutely spinulose. Conspicuous midrib extending 

to leaf apex, with one intramarginal vein on each 

side that is connected only at the base of the 

midrib and joining it again just below the tip. 

Cross-veins absent. 

NATURAL HISTORY.—Halophila beccarii occurs in 

the shallow, intertidal zone in sheltered localities, 

such as mangroves, mouths of rivers, and brackish 

ponds. Th e plant seems to favor sand-mud, particularly muddy substrates. In Singapore, samples 

of the species were found abundant on mu d and 
NUMBER 21 25 

FIGURE 16.—Enhalus acoroides: top, world distribution; bottom, Philippine distribution. 
26 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 17.—Halophila beccarii: A, habit of plant, X 2.9; B, leaves showing entire and spinulose 

margins, including conspicuous midrib and intramarginal veins, X 7.3. 

on sand in shaded stream beds, and in brackish 

water in mangroves. Flowering of Halophila beccarii have been observed during February, June , 

and August. The plant may be found growing in 

pure stand or together with Halophila ovalis, H. 

minor, or Halodule uninervis. A few patches of crustose melobesioids were observed growing on 

leaves of Halophila beccarii collected from the Philippines. 

PHILIPPIN E DISTRIBUTION.—Luzon (Manila 

Bay, Paranaque). 

RANGE.—H. beccarii occurs in Chilka Lake, a 

salt-water lake along the eastern coast of India. It 

has also been recorded in Sri Lanka, Burma, 

Vietnam, and Malaysia. 

Halophila minor (Zollinger) den Hartog 

FIGURES 19A-C, 20 

Lemnopsis minor Zollinger, 1854:75. 

Halophila minor (Zollinger) den Hartog, 1957:410.-

and del Rosario, 1967:21. 

-Mendoza 
NUMBER 21 27 

FIGURE 18.—Halophila beccarii: top, world distribution; bottom, Philippine distribution. 
28 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 19.—Halophila minor:A, habit of plant, X 4.9; B, leaf showing cross veins, X 9.7; c, scale, 

X 29.1. 
NUMBER 21 29 

FIGURE 20.—Halophila minor: top, world distribution; bottom, Philippine distribution. 
30 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

Halophila ovata sensu Ostenfeld, 1909:68.—sensu Merrill, 

1912:70; 1925:26.—sensu den Hartog, 1970:251. [Non 

Gaudichaud, 1826 [1829]: 430 (= H. ovalis (R. Brown) 

Hooker f.).] 

CHARACTERISTICS.—This is probably the smallest of the seagrasses found in the Philippines, with 

rhizomes barely reaching 1 mm in diameter; 

internodes 7-20 mm long; usually one root below 

each erect shoot. Erect shoot short, consisting of 

a pair of leaves on each node. Leaves with petioles, 2-8 mm long, each enveloped by a pair of 

transparent, orbicular scales with rounded apices. 

Leaf blades elliptic or obovate, width 2-3 mm, 

length 4-7 mm, apices rounded, bases attenuate; 

margins entire; with 4-7 pairs of cross-veins. 

Staminate flowers pedicellate, with obtuse, convex tepals; anthers approximately 2 mm long. 

Pistillate flowers with 3 styles, each up to 15 mm 

long; ovary ovoid, reaching a length of 3 mm. 

Ellipsoid, ovoid or globose fruits u p to 4 mm long, 

bearing 2-6 mm long beaks; seeds subglobose, 

about 0.5 mm long. 

The authors follow the remarks of Sachet and 

Fosberg (1973:441) that the correct name for this 

species is Halophila minor, since Halophila ovata is a 

superfluous name, hence illegitimate. 

NATURAL HISTORY.—Halophila minor occurs in 

sheltered coasts on mud, sand, or coral rubble 

substrates. The plant seems to prefer muddy bottoms and tolerates heavy sedimentation, as generally found in deep bay localities that are well 

protected from wave action. In the Philippines, 

H. minor plants were collected from sand-mud or 

coral rubble substrates during January-May . 

They were abundant in March-Ma y and bearing 

flowers and fruits. Flowering plants have been 

observed in Januar y and in April, including 

fruits, at New Caledonia. Plants with fruits and 

flowers were collected from Kenya in July. Den 

Hartog (1970) suggested that in areas where the 

plants are reproductive, they are annuals, and in 

places where they do not flower, they may be 

perennials. Halophila minor have been found growing together with Halophila ovalis, Enhalus acoroides, 

Thalassia hemprichii, and Halodule uninervis. Examination of epiphytes revealed few patches of crustose red algae on leaves of H. minor from the 

Philippines. 

PHILIPPIN E DISTRIBUTION.—Luzon (Manila 

Bay, Albay, Mindoro); Visayas (Cebu, Negros). 

RANGES.—Halophila minor occurs in Kenya, India, Singapore, Indonesia, Papua. New Guinea, 

Western Australia, Queensland, New Caledonia, 

Samoa, Fiji, Wallis Islands, Caroline Islands, 

Mariana Islands, Hawaii. 

Halophila ovalis (R. Brown) Hooker f. 

FIGURES 21A-C, 22 

Caulinia ovalis R. Brown, 1810:339. 

Halophila ovalis (R. Brown) Hooker, 1858:45.—Merrill, 

1925:26.—Domantay, 1962:275.—Mendoza and del Rosario, 1967:22.—den Hartog, 1970:240.—Cordero, 1981: 

322. 

Halophila ovata Gaudichaud, 1826 [1829]:430. 

CHARACTERISTICS.—Plants small, with long and 

narrow rhizomes, not more than 2 mm in diameter; internodes 5-40 mm long; usually one root 

present below each erect shoot. Erect shoot short, 

consisting of a pair of leaves borne on each node. 

Leaves petiolated; petioles 5-50 mm long, each 

enveloped by a pair of transparent scales; apex of 

scale emarginate, the base auriculate. Leaf blades 

oblong, oval, elliptic or spathulate, occasionally 

lanceolate or linear, width 4-12 mm, length 8-

25 mm, apices rounded, bases cuneate, attenuate 

or truncate; margins entire; with 12-22 pairs of 

cross-veins which are often forked. Midrib connected to the intramarginal nerve at the top. 

Staminate flowers consist of small, elliptic, convex 

tepals generally obtuse or slightly apiculate; anthers oblong. Pistillate flowers with small ovoid 

ovaries; 3 long styles. Fruits globose with beaks 

up to 6 mm long. 

NATURAL HISTORY.—Halophila ovalis occurs in 

open or sheltered coasts, from midtide to 10 m 

deep in Central Philippines. Th e plant grows on 

a wide variety of substrate, such as mud, living 

corals, or coral rubble, and in sand where the 

plant is occasionally almost completely buried. 

According to the literature, H. ovalis is a euryhaline species that can grow in waters with de-
NUMBER 21 31 

FIGURE 21.—Halophila ovalis: A, habit of plant, X 2.2; B, leaf showing cross veins, X 5.6; c, scale, 

X 10.4. 
32 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 22.—Halophila ovalis: top, world distribution; bottom, Philippine distribution. 
NUMBER 21 33 

creased salinities of 10%o, as in estuaries and 

brackish lagoons. It is also eurythermic, but cannot survive in waters with temperatures below 

10° C. There is a great variability in its morphology (i.e., leaf size and shape, plant size, nervation) which is probably influenced primarily 

by its environment. In den Hartog's (1970) view, 

H. ovalis represents a "collective species" and only 

H. ovata (= H. minor) had been separated from it 

(Ostenfeld, 1909). 

Halophila ovalis is an abundant seagrass in tropical and warm temperate areas, occasionally 

found in pure stands or mixed with Thalassia 

hemprichii, Halodule uninervis, H. pinifolia, Cymodocea 

rotundata, or Enhalus acoroides. On a sand-bar on 

the northwestern end of Sumilon Island, Philippines, it was observed that Halophila ovalis appeared as a pioneer species on new sand-coral 

rubble substrate. The plant flowers and fruits 

during the warmest months. Algal epiphytes 

found on the leaves of the plant include crustose 

melobesioids, a few thalli of species of Acrochaetium, Ceramium, Hypnea, Jania, and Polysiphonia. 

PHILIPPINE DISTRIBUTION.—Luzon (La Union, 

Catanduanes, Pangasinan, Albay, Mindoro, 

Masbate); Palawan (Cuyo Islands, Quezon); Visayas (Leyte, Negros, Cebu, Panay, Sumilon, Siquijor, Bohol, Samar); Mindanao (Davao, Zamboanga, Bancoran Island). 

RANGE.—Halophila ovalis is widely distributed 

in the Indo-West Pacific. It occurs in Egypt, 

Sudan, Kenya, Tanzania, Mozambique, South 

Africa, Madagascar, Seychelles, Mauritius, Israel, 

Saudi Arabia, Yemen, Kuwait, Iran, Bahrain 

Islands, Sri Lanka, Burma, Andama n Islands, 

Thailand, Vietnam, Hong Kong, China, Ryukyu 

Islands, Malaysia, Indonesia, Papua New Guinea, 

Western Australia, South Australia, Tasmania, 

New South Wales, Lord Howe Island, Queensland, Northern Territory, Caroline Islands, Hawaiian Islands, Samoa Islands, Tonga Islands, 

Fiji Islands, New Caledonia, and India. 

Halophila spinulosa (R. Brown) Ascherson 

FIGURES 23A,B, 24 

Caulinia spinulosa R. Brown, 1810:339. 

Halophila spinulosa (R. Brown) Ascherson, 1875:368.—Merrill, 1915:2; 1925:26.—Pascasio and Santos, 1930:4.—Domantay, 1962:275.—Mendoza and del Rosario, 1967: 

22.—den Hartog, 1970:263. 

CHARACTERISTICS.—Plants small, with long and 

narrow rhizomes, not more than 1 mm in diameter; internodes 13-35 mm long; usually one root 

per node; roots 5-10 cm long, beset with filiform 

hairs. Erect shoots pedicellate with 2 basal, ovate 

scales with serrate apex. Sessile leaf blades up to 

22 pairs, distichously arranged on erect shoot; 

blades oblong-linear, semi-amplexicaulous, 20 

mm long, 3.5 mm wide; margins serrate; basal 

portion of one side of blade folded; a few inconspicuous cross-veins present and connected to the 

intramarginal nerve; tip of conspicuous midrib 

joining intramarginal nerve. 

NATURAL HISTORY.—Halophila spinulosa occurs 

on sand, mud, or coral rubble in the sublittoral 

zone. Th e plant may grow together with Thalassia 

hemprichii, Enhalus acoroides, Halophila ovalis, and 

Halodule pinifolia. Flowering H. spinulosa has been 

observed during March, October, November, and 

December. Fruits were observed in October. Th e 

plant can tolerate brackish water conditions (den 

Hartog, 1970). The few specimens of//, spinulosa 

examined did not reveal any epiphytes. 

PHILIPPINE DISTRIBUTION.—Luzon (Manila 

Bay, Mindoro, Camarines); Mindanao (Davao). 

RANGE.—Halophila spinulosa occurs in Malaysia, 

Singapore, Indonesia, Western Australia, Papua 

New Guinea, and Queensland. 

Thalassia hemprichii (Ehrenberg) Ascherson 

FIGURES 25A,B, 26 

Schizotheca hemprichii Ehrenberg, 1836:429. 

Thalassia hemprichii (Ehrenberg) Ascherson, 1871c:242.— 

Merrill, 1912:71; 1925:27.—Pascasio and Santos, 1930:1, 

figs. 1-52, plates 1-5.—Domantay, 1962:276.—Mendoza 

and del Rosario, 1967:50.—den Hartog, 1970:232, fig. 

61.—Cordero, 1981:323, fig. 3. 

CHARACTERISTICS.—Plants of moderate size, 

consisting of a robust rhizome, 2-4 mm in diameter; internodes 3-6 mm long; roots clothed with 

dense filiform laterals, one per node if present. 

Erect shoot short, with 2-6 leaves enveloped by 
34 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 23.—Halophila spinulosa: A, habit of plant, X 0.95; B, portion of erect shoot with two 

amplexicaulous leaves, showing folded basal end, X 3.1. 
NUMBER 21 35 

FIGURE 24.—Halophila spinulosa: top, world distribution; bottom, Philippine distribution. 
36 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

FIGURE 25.— Thalassia hemprichii: A, habit of plant, X 1.0; B, upper portion of leaf showing 

perpendicular nerves connected by cross veins, X 4.0. 

3-8 cm-long sheaths; erect shoots sparsely distributed along rhizome. Leaf blades linear and distinctly falcate (particularly in less grazed areas), 

4-10 mm wide, 7-40 cm long (commonly less 

than 25 cm long), apices rounded, occasionally 

uneven, margins entire; 10-16 nerves connected 

by cross-veins; median nerve often conspicuous. 

NATURAL HISTORY.— Thalassia hemprichii is com-
NUMBER 21 37 

FIGURE 26.— Thalassia hemprichii: top, world distribution; bottom, Philippine distribution. 
38 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

mon on mud-coral-sand or coarse coral-sand substrates, in sheltered habitats in the Philippines. 

T h e plant has been observed growing from the 

base and through fingers of corals at 6 m deep. T. 

hemprichii may be found mixed with Syringodium 

isoetifolium, Cymodocea serrulata, C. rotundata, Enhalus 

acoroides, Halophila ovalis, and Halodule uninervis. At 

several sites in Negros, Philippines, T hemprichii 

appeared to be "mowed down" in large patches 

and there was evidence of fish grazing on the 

leaves of the plant. Algal epiphytes observed on 

the leaves include species of Centroceras, Cladophora, 

Erythrotrichia, Fosliella, Giffordia, Herposiphonia, and 

Polysiphonia. Flowering of T hemprichii occurs during January, February, and December in the 

Philippines. 

PHILIPPIN E DISTRIBUTION.—Luzon (Manila 

Bay, Pangasinan, Catanduanes, Albay, Batangas, 

Cagayan, Mindoro, La Union, Ilocos Norte); Palawan (Quezon); Visayas (Samar, Siquijor, Cebu, 

Leyte, Bohol, Negros); Mindanao (Surigao, Davao, Cavili Island). 

RANGE.— Thalassia hemprichii is common in the 

tropical region of the Indian Ocean and western 

part of the Pacific. It occurs in Sudan, Eritrea, 

Somalia, Kenya, Tanzania, Mozambique, Seychelles, Aldabra Islands, Madagascar, Saudi Arabia, Yemen, Andaman Islands, Thailand, Vietnam, Ryukyu Islands, Malaysia, Indonesia, 

Papua New Guinea, Caroline Islands, Marshall 

Islands, Bismarck Archipelago, New Caledonia, 

and Queensland. 
Literature Cited 

Ascherson, P. 

1868. Vorarbeiten zu einer Uebersicht der phanerogamen Meeresgewachse. Linnaea, 35:152-208. 

1871a. [Untitled report.] Sitzungs-Bericht der Gessellschaft 

Naturforschender Freunde zu Berlin, 1870:77-91. 

1871b. Plantae phanerogamae marinae in archipelago Indico et in Mari Rubro. Nuovo Giomale di Botanica 

Italiana, 3:299-302. 

1871c. Die geographische Verbreitung der Seegraser. In 

Petermanns Geographische Mitteilungen, 17:241-248, 

plate 13. 

1875. Die geographische Verbreitung der Seegraser. In 

G. Neumayer, Anleitung zu Wissenschaftlichen Beobachtungen auf Reisen, pages 361-373. Berlin. 

Blanco, P. fr. M. 

1837. Flora de Filipinos, segun el sistema sexual de Linneo. 

lxxviii + 887 pages. Manila: Imprenta de Sto. 

Thomas por D. Candido Lopez. 

1845. Flora de Filipinos, segun el sistema sexual de Linneo. 

2nd edition, lix + 619 pages. Manila: Imprenta 

de D. Miguel Sanchez. 

1879. Flora de Filipinos, Gran Edicion. 3rd. edition, v + 271 

pages. Manila: Establecimiento Tipografico de 

Plana y Cia. 

Boissier, E. 

1882. Flora orientalis sive enumeratio plantarum in Oriente a 

Graecia et Aegypto ad Indiae fines hucusque observatarum. 

Volume 5 (Monocotyledearum, Gymnospermae, 

Acotyledoneae vasculares), 868 pages. Genevae et 

Basileae: H. Georg. Bibliopulam. 

Brown, R. 

1810. Prodromus florae Novae Hollandiae et Insulae Van-Diemen, exhibens characteres plantarum quas annis 1802-

1805 per oras Utriusque insulae collegit et descripsit 

Robertus Brown. Volume 1, 592 pages. London: 

Typis Richardi Taylor et Sociee, veneunt apud J. 

Johnson et socios, in coemeterio Sancti Pauli. 

Calumpong, H.P. 

1979. Some Aspects of the Ecology of the Sea Hare, 

Dolabella auricularia (Lightfoot) in Central Visayas, 

Philippines. Silliman Journal, 26:134-146. 

Cordero, P.A. 

1981. Some Seagrasses from the Philippines. Publication 

of the Seto Marine Biological Laboratory, 26:319-325, 

figures 1-3. 

Dandy, J.E., and G. Tandy 

1939. On the Identity of Syringodium Kiitz. Journal of 

Botany, British and Foreign, 77(916): 114-116. 

den Hartog. See Hartog. 

Domantay, J.S. 

1962. An Ecological Survey of the Marine Vegetation of 

the Hundred Islands and Vicinity. Philippine Journal of Science, 90:271-293. 

Ehrenberg, C.G 

1836. Das Leuchten des Meeres: Neue Beobachtungen 

nebst Uebersicht der Hauptomomente der geschichtlichen Entwicklung dieses merk-Wiirdigen 

Phanomens. Abhandlungen der Kdniglichen Akademie 

der Wissenschaften zu Berlin, 1834:411-575, 2 plates. 

Engler, A., and K. Prantl 

1897. Die natiirlichen Pflanzenfamilien. Volume 2, 380 

pages. Leipzig. 

Forskal, P. 

1775. Flora Aegyptiaco-Arabica. 219 pages. Copenhagen. 

Gaudichaud, M.D. 

1826 [1829]. Botanique. In M.L. Freycinet, Voyage autour 

du monde, entrepris par ordre du roi...execute sur les 

corvettes de S.M. l'Uranie et la Physicienne pendant 

les annees 1817, 1818, 1819, 1820, par Louis de 

Freycinet. 522 pages. 

Hartog, C. den 

1957. Hydrocharitaceae. Flora Malesiana, series 1, 5:381-

413. 

1964. An Approach to the Taxonomy of the Seagrass 

Genus Halodule Endl. (Potamogetonaceae). Blumea, 

12(2):289-312. 

1970. Seagrasses of the World. 275 pages, 63 figures. Amsterdam, London: North-Holland Publishing 

Company. 

Hooker, J.D. 

1858. Flora Tasmaniae. In The Botany of the Antarctic 

Voyage of H.M. Discovery Ships Erebus and Terror, in 

the Years 1839-1843, under the Command of Captain 

Sir James Clark Ross, 3(2): 416 pages. London: 

Lovell Reeve. 

Isaac, F.M. 

1968. Marine Botany of the Kenya Coast, IV: Angiosperms. Journal of East African Natural History Society, 

National Museum, 27:29-47. 

Johnstone, I.M. 

1979. Papua New Guinea Seagrasses and Aspects of the 

Biology and Growth of Enhalus acoroides (L. f.) 

Royle. Aquatic Botany, 7:197-208. 

1982. Ecology and Distribution of Seagrasses. In J.L. 

Gressitt, editor, Biogeography and Ecology of New 

Guinea. Monographiae Biologicae, 42:497-512. 

39 
40 SMITHSONIAN CONTRIBUTIONS TO THE MARINE SCIENCES 

Kay, Q.O.N. 

1971. Floral Structure in the Marine Angiosperms Cymodocea serrulata and Thalassodendron ciliatum (Cymodocea ciliata). Journal of Linnean Society of London 

(Botany), 64:423-429. 

Kirkman, H. 

1975. Male Floral Structure in the Marine Angiosperm 

Cymodocea serrulata (R. Br.) Ascherson and Magnus 

(Zannichelliaceae). Journal of Linnean Society of London (Botany), 70:267-268. 

Linnaeus, C, f. 

1781. Supplementum Plantarum Systematis Vegetabilium editionis decimae tertiae, Generum Plantarum editionis sextae 

et Specierum Plantarum editionis secundae. 467 pages. 

Brunsvigae: Impenfis Orphanotrophei. 

McMillan, C. 

1980a. Flowering under Controlled Conditions by Cymodocea serrulata, Halophila stipulacea, Syringodium isoetifolium, Zostera capensis, and Thalassia hemprichii 

from Kenya. Aquatic Botany, 8:323-336. 

1980b. Staminate Flowers under Controlled Conditions 

by Cymodocea serrulata from Kenya. Aquatic Botany, 

9:291-295. 

1983. Morphology of Cymodocea serrulata from Yap, Micronesia, Kept under Controlled Light Conditions. Aquatic Botany, 15:209-215. 

McMillan, C, K. Bridges, R. Kock, and M. Falanruw 

1982. Fruit and Seedlings of Cymodocea rotundata in Yap, 

Micronesia. Aquatic Botany, 14:99-105. 

Mendoza, D., and R. del Rosario 

1967. Philippine Aquatic Flowering Plants and Ferns. Publication Number 1, 53 pages. Manila: Philippine 

National Museum. 

Menez, E., and H. Calumpong 

1983. Thalassodendron ciliatum: An Unreported Seagrass 

from the Philippines. Micronesica, 18(2): 103—111. 

Merrill, E.D. 

1912. A Flora of Manila. Philippine Islands Bureau of Science, Publication, 5: 490 pages. Manila: Bureau of 

printing. 

1915. New and Noteworthy Philippine Plants. Philippine 

Journal of Science, 10(1): 1 -84. 

1918. Species Blancoanae, a Critical Revision of the 

Philippine Species of Plants Described by Blanco 

and by Llanos. Philippine Islands Bureau of Science, 

Publication, 12: 423 pages. Manila: Bureau of printing. 

1925. An Enumeration of Philippine Flowering Plants. 

Philippine Islands Bureau of Science, Publication, 18(1): 

463 pages. Manila: Bureau of printing. 

Miki, S. 

1932. On Seagrasses New to Japan. Botanical Magazine, 

46(552): 774-788. 

Ostenfeld, CH . 

1909. On Halophila ovata Gaudichaud, a Neglected Species. Philippine Journal of Science, 4:67-68. 

Pascasio, J.F., and J.K. Santos 

1930. A Critical Morphological Study of Thalassia hemprichii (Ehrenb.) Aschers. University of the Philippines 

Natural and Applied Science Bulletin, 1: 24 pages, 52 

figures, 5 plates. 

Royle, J.F. 

1840. Illustrations of the Botany and Other Branches of Natural 

History of the Himalayan Mountains and of the Flora of 

Cashmere. Volume 1, 472 pages. London: William 

H. Allen and Company. 

Sachet, M.-H., and F.R. Fosberg 

1973. Remarks on Halophila (Hydrocharitaceae). Taxon, 

22(4):439-443. 

Thayer, G., A. Wolfe, and R. Williams 

1975. The Impact of Man on Seagrass Systems. American 

Scientist, 63:288-296. 

Tsuda, R.T., F.R. Fosberg, and M.-H. Sachet 

1977. Distribution of Seagrasses in Micronesia. Micronesica, 13:191-198. 

Zollinger, H. 

1854. Systematisches Verzeichniss den im indischen Archipel in 

denjahren 1842-1848 gesammelten sowie der ans Japan 

empfangenen pflanzen. Volume 1, xii + 160 pages. 

Zurich: Driick und Verlag von E. Kiesling. 
REQUIREMENTS FOR SMITHSONIAN SERIES PUBLICATION 

Manuscripts intended for series publication receive substantive review within their originating Smithsonian museums or 

offices and are submitted to the Smithsonian Institution Press 

with Form SI-36, which must show the approval of the appropriate authority designated by the sponsoring organizational unit. 

Requests for special treatment—use of color, foldouts, casebound covers, etc.—require, on the same form, the added 

approval of the sponsoring authority. 

Review of manuscripts and art by the Press for requirements 

of series format and style, completeness and clarity of copy, and 

arrangement of all material, as outlined below, will govern, within 

the judgment of the Press, acceptance or rejection of manuscripts and art. 

Copy must be prepared on typewriter or word processor, 

double-spaced, on one side of standard white bond paper (not 

erasable), with 1% " margins, submitted as ribbon copy (not 

carbon or xerox), in loose sheets (not stapled or bound), and 

accompanied by original art. Minimum acceptable length is 30 

pages. 

Front matter (preceding the text) should include: title page 

with only title and author and no other information; abstract 

page with author, title, series, etc., following the established 

format; table of contents with indents reflecting the hierarchy of 

heads in the paper; also, foreword and/or preface, if appropriate. 

First page of text should carry the title and author at the top 

of the page; second page should have only the author's name 

and professional mailing address, to be used as an unnumbered 

footnote on the first page of printed text. 

Center heads of whatever level should be typed with initial 

caps of major words, with extra space above and below the 

head, but with no other preparation (such as all caps or underline, except for the underline necessary for generic and specific 

epithets). Run-in paragraph heads should use period/dashes or 

colons as necessary. 

Tabulations within text (lists of data, often in parallel columns) 

can be typed on the text page where they occur, but they should 

not contain rules or numbered table captions. 

Formal tables (numbered, with captions, boxheads, stubs, 

rules) should be submitted as carefully typed, double-spaced 

copy separate from the text; they will be typeset unless otherwise requested. If camera-copy use is anticipated, do not draw 

rules on manuscript copy. 

Taxonomic keys in natural history papers should use the 

aligned-couplet form for zoology and may use the multi-level 

indent form for botany. If cross referencing is required between 

key and text, do not include page references within the key, but 

number the keyed-out taxa, using the same numbers with their 

corresponding heads in the text. 

Synonymy in zoology must use the short form (taxon, author, 

yeanpage), with full reference at the end of the paper under 

"Literature Cited.'' For botany, the long form (taxon, author, 

abbreviated journal or book title, volume, page, year, with no 

reference in "Literature Cited") is optional. 

Text-reference system (author, yeanpage used within the 

text, with full citation in "Literature Cited" at the end of the text) 

must be used in place of bibliographic footnotes in all Contributions Series and is strongly recommended in the Studies 

Series: "(Jones, 1910:122)" or "...Jone s (1910:122)." If 

bibliographic footnotes are required, use the short form (author, 

brief title, page) with the full citation in the bibliography. 

Footnotes, when few in number, whether annotative or bibliographic, should be typed on separate sheets and inserted 

immediately after the text pages on which the references occur. 

Extensive notes must be gathered together and placed at the 

end of the text in a notes section. 

Bibliography, depending upon use, is termed "Literature 

Cited," "References," or "Bibliography." Spell out titles of 

books, articles, journals, and monographic series. For book and 

article titles use sentence-style capitalization according to the 

rules of the language employed (exception: capitalize all major 

words in English). For journal and series titles, capitalize the 

initial word and all subsequent words except articles, conjunctions, and prepositions. Transliterate languages that use a nonRoman alphabet according to the Library of Congress system. 

Underline (for italics) titles of journals and series and titles of 

books that are not part of a series. Use the parentheses/colon 

system for volume(number):pagination: "10(2):5-9." For alignment and arrangement of elements, follow the format of recent 

publications in the series for which the manuscript is intended. 

Guidelines for preparing bibliography may be secured from 

Series Section, SI Press. 

Legends for illustrations must be submitted at the end of the 

manuscript, with as many legends typed, double-spaced, to a 

page as convenient. 

Illustrations must be submitted as original art (not copies) 

accompanying, but separate from, the manuscript. Guidelines 

for preparing art may be secured from Series Section, SI Press. 

All types of illustrations (photographs, line drawings, maps, etc.) 

may be intermixed throughout the printed text. They should be 

termed Figures and should be numbered consecutively as they 

will appear in the monograph. If several illustrations are treated 

as components of a single composite figure, they should be 

designated by lowercase italic letters on the illustration; also, in 

the legend and in text references the italic letters (underlined in 

copy) should be used: "Figure 9b." Illustrations that are intended to follow the printed text may be termed Plates, and any 

components should be similarly lettered and referenced: "Plate 

9b." Keys to any symbols within an illustration should appear 

on the art rather than in the legend. 

Some points of style: Do not use periods after such abbreviations as "mm, ft, USNM, NNE." Spell out numbers "one" 

through "nine" in expository text, but use digits in all other 

cases if possible. Use of the metric system of measurement is 

preferable; where use of the English system is unavoidable, 

supply metric equivalents in parentheses. Use the decimal system for precise measurements and relationships, common fractions for approximations. Use day/month/year sequence for 

dates: "9 April 1976." For months in tabular listings or data 

sections, use three-letter abbreviations with no periods: "Jan, 

Mar, Jun," etc. Omit space between initials of a personal name: 

"J.B. Jones." 

Arrange and paginate sequentially every sheet of manuscript in the following order: (1) title page, (2) abstract, (3) 

contents, (4) foreword and/or preface, (5) text, (6) appendixes, 

(7) notes section, (8) glossary, (9) bibliography, (10) legends, 

(11) tables. Index copy may be submitted at page proof stage, 

but plans for an index should be indicated when manuscript is 

submitted.