ANDSCAPE L INES

INTRODUCTION

Pollen, phytolith, and macrofloral analyses are archeological techniques

used to investigate the prehistory and history of vegetation types within

a landscape. Data from these analyses provides information about

former land use and changes in cultural activities over time. (See Figure

1.) Archeological and ethnobotanical expertise is required to analyze

pollen, phytoliths, and macroflora.

The potential for pollen, phytolith, and macrofloral analyses to yield

data about vegetation is highest when a site is undisturbed (for example, a site that has not received fill material or been inundated by

flooding). In addition, information about a site is enhanced when the

three techniques are conducted together. (The three analyses also

complement other archeological techniques, such as the analysis of

material artifacts.)

A pollen grain is the microscopic, single-celled male gamete of a

flowering plant and a phytolith is a mineral fossil cast of a plant. The

term, macroflora, refers to seeds and other macroscopic plant

remains, such as wood, leaves, tubers, and flowers, that are preserved within an incubating sediment, such as soil. The remains of

pollen, phytoliths, and macroflora can be collected from soil samples

of a known deposition level within a soil profile. Based on their

taxonomic classification and the soil strata in which they exist, the

extant plant community of a prehistoric or historic period can be

determined. In addition, the extent to which the pollen, phytolith,

and macroflora remains are corroded or degraded can indicate the

relative age of the sample.

7

Pollen, Phytolith, and Macroflora Analyses
2 L A N D S C A P E L I N E S

POLLEN ANALYSIS

The Technique

To analyze pollen, a small soil sample is taken from

each stratigraphic layer that has been excavated by

an archeologist. Systematic excavations allow for

classification of soils by temporal sequence, which

creates reference points for analyzing the changes

in a landscape over time. The classified soil samples

are sent to a palynologist for pollen analysis. Because there are not many archaelogical palynologists in the United States, the analysis may take

three to six months. Currently, the cost of analysis

ranges from $85.00 to $150.00 per soil sample.

Figure 1. Photograph of Boott Cotton Mills and Yard, the site of numerous archeological investigations that included pollen and phytolith

analyses. Lowell National Historical Park. (Photograph courtesy of the University of Massachusetts at Lowell, 1890)

The pollen analysis of sediment taken from sample

cores in wetlands may reveal more than soil samples

taken from an archaeological excavation. There are

two reasons for this: first, pollen grains are better

preserved in wetland cores because there is less

microbiotic activity, and second, wetland cores reveal

more about the intervals between human and natural

disturbances, such as fire, pathogens, and climate.

(The occurrence of fire is determined by counting

charcoal particles found in pollen samples.)

Preserved pollen grains are extracted from an

incubating sediment, such as soil, by chemical and

mechanical separation treatments. Then the grains
P O L L E N , P H Y T O L I T H , A N D M A C R O F L O R A L A N A L Y S E S 3

are examined under a microscope to identify

characteristics of the parent plant. Although some

pollen can be classified at the subgenus or species

level, most pollen cannot be identified below the

level of genus. Some plant taxa have similar pollen

characteristics, making it difficult to identify the plant

below the level of family. For instance, chenopod

and amaranth grass families are difficult to distinguish from just their pollen grains. Nearly every

family of flowering plant has been investigated

palynologically, though the accuracy of pollen

information varies with each family. Palynologists

can identify both dicotyledonous and monocotyledonous plants from their pollen, as well as fern

spores, fungal spores, and algal cysts and spores.

Pollen can persist in soils for a long time, although its

longevity is determined by such factors as exposure

to oxygen, grain size, the initial abundance of pollen

from a particular species, and durability of the pollen

grain wall. The percentages of different taxa, determined by identifying pollen, does not necessarily

represent the relative composition of vegetation in a

particular period; rather, it indicates the presence of

a particular plant community or taxa. While pollen

preservation is generally poor in prehistoric sites,

recent work indicates that pollen preservation in

historic sites is generally adequate enough to yield

valuable information about plant communities.

Applying Pollen Analysis to

Cultural Landscape Research

Pollen analysis was originally used by paleoecologists

to reconstruct the prehistoric environment. In

recent years, archeologists have used pollen analysis

to identify the plant communities that were extant in

particular historic periods and relate vegetation

changes over time to land use. Pollen data can also

reveal information about climatic and ecological

conditions within a particular period.

Pollen analysis has been used to chronicle the

introduction of European flora with increased

mercantile trade into the early colonies. For

example, changing land use patterns in seventeenth century Jamestown, Virginia have been

identified from preserved pollen. Similar patterns

were identified at Lowell National Historical Park

in Massachusetts and Harpers Ferry National

Historical Park in West Virginia. In both of these

landscapes, the pollen record indicated a transition from well maintained yards around dwellings

at the turn of the nineteenth century to more

unkempt, weedy environments corresponding

with the period of the industrial revolution.

The presence of pollen in a soil sample indicates

that a particular genus of plant was historically

present in the vicinity, but it does not indicate the

precise location of a particular plant taxa. This is

due to the natural forces of wind and water that

can affect the deposition and incubation of pollen.

To determine the historical location of a plant

taxa, soil samples must be analyzed for phytoliths,

the mineral fossil casts of plants.

PHYTOLITH ANALYSIS

The Technique

Phytolith analysis is most often used to reconstruct vegetation cover over time. Phytoliths are

released into the soil by plant decay, deposits of
4 L A N D S C A P E L I N E S

plant tissue in the soil through waste, and through

cultural processing of plant tissue as fuel, food,

fiber, or building material. The presence of

phytoliths indicates the location of a plant, animal,

or cultural activity, and can be used to reconstruct

the microdistribution—the relative historic

locations—of plants.

Phytoliths are formed when hydrated silicon

dioxide precipitates out within plant cells and is

deposited along cell walls, where it forms a

hard, opaline microfossil cast. The phytoliths

remain within the living plant and are released

into the soil when the tissue is digested by

decay organisms. Phytoliths are known to be

very stable in the soil (typically more decayresistant than pollen) and therefore may yield

information about prehistoric conditions of a

landscape. Phytoliths occur mostly in stems and

leaves, though they may also form in root,

flower, and fruit cells. Unlike pollen, phytoliths

are associated with more than just flowering

plants, so they have the potential to provide

more information about the plant kingdom in a

particular period.

Phytolith and pollen analysis are complementary

techniques, with their relative strengths in

monocotyledon and dicotyledon identification,

respectively. Like pollen, phytoliths are identified

through their morphological characteristics. A

paleobotanist may perform the pollen and

phytolith analyses concurrently. For the benefit

of integrating pollen and phytolith data, pollen

and phytoliths should be derived from the same

soil samples.

Applying Phytolith Analysis to

Cultural Landscape Research

Phytolith analysis is particularly revealing for

monocotyledonous plants, especially the grass

family. Many genera of grasses can be identified, yielding valuable ethnobotanical information about the cultural importance of grasses as

food crops, building materials, and ornamental

plants. For example, the presence of turf-grass

phytoliths may indicate lawns in cultural landscapes.

At Lowell National Historical Park in Massachusetts and at Harpers Ferry National Historical

Park in West Virginia, phytolith analysis was used

in conjunction with pollen and artifact analysis to

document change in land use during the industrial revolution of the nineteenth century. (See

Figures 2 and 3.) At Hampton, Virginia, archeological investigations within the early city recovered teeth from domestic livestock. Phytoliths

were extracted from the deposits on the teeth,

providing a physical record of the eighteenth and

nineteenth century diets of livestock and domestic animals. This information has been used to

interpret 150 years of change in husbandry

practices and land use at the household and

community levels. The analysis of phytoliths was

also used to identify historic field crop patterns at

Monticello in Virginia, garden flora at the

Moravian Gardens in North Carolina, Bacon’s

Castle in Virginia, and Morvan Gardens in New

Jersey.
P O L L E N , P H Y T O L I T H , A N D M A C R O F L O R A L A N A L Y S E S 5

Figure 2. The Harper Yard is the site of numerous archeological investigations that included phytolith analysis. Information yielded in

part through phytolith analysis contributed to a treatment plan proposing rehabilitation of the yard to reflect its nineteenth century

character as a residential garden. Harpers Ferry National Historical Park. (NPS, 1991)

Figure 3. The proposed treatment plan for the Harper Yard. Information for the rehabilitation plan was partly derived from phytolith

and pollen analyses of the yard. Harpers Ferry National Historical Park. (NPS, 1991)
6 L A N D S C A P E L I N E S

MACROFLORA ANALYSIS

The Technique

Macroflora analysis refers to the investigation of

the macroscopic, buried remains of plants. These

macroscopic remains include seeds, fruits, wood,

leaves, roots, and tubers. Macroflora are identified according to their parent taxa and used to

construct a history of indigenous and introduced

vegetation. Macroflora are also a source of

ethnobotanical information, which indicates the

relationship between the plants and cultural

activities of a landscape.

Macroflora are preserved for the longest duration in charcoalified form, caused by charring

through human activities or naturally occurring

fires. Charcoal (carbon) is a relatively inert substance that is not further decomposed by microorganisms. Few seeds live longer than a century

and those persisting longer are usually charred.

Carbon dating can be used to determine the

relative age of charcoalified macroflora.

In the absence of charring, macroflora are best

preserved in incubating conditions that are least

favorable to the growth of decomposing microorganisms. Such conditions include arid, dry environments and conditions with a pH either more

acid or alkaline than neutral. Most living organisms

occupy a narrow pH range from slightly acid to

neutral. More acid conditions, such as found in

bogs and privies, retard the decomposition of

organic material (macroflora) because the pH

inhibits the growth of microorganisms. Anaerobic,

waterlogged conditions are conducive to the

carbonization of macroflora, a process similar to

lignification (development of wood), which also

retards decomposition.

Macroflora are derived from soil samples that have

been classified according to their strata. Seeds may

be incubated within human or mammalian waste

(where they can provide dietary information), or

directly within soil as a result of dispersal by wind,

animals, and water. The macroflora analyst separates the seeds, leaves, fruits, or wood from the

incubating sediment and observes the tissue under

a light microscope to identify the parent taxa.

Seeds and whole leaves can often be identified to

the species level through examination of morphological characteristics. Certain dry fruits or succulent

fruits, such as cherries and peaches, are identifiable

to species. Wood must be diagnosed through the

microscopic examination of conductive tissues and

generally cannot be identified below the taxonomic

level of genus.

Applying Macroflora Analysis to

Cultural Landscape Research

Macroflora analysis is used with other archeological techniques to reconstruct the historic appearance of a cultural landscape. Charcoalified

macroflora may be used to reconstruct vegetation

cover in prehistoric periods. The analysis may

indicate the presence of plant species in a particular period and also provide a temporal sequence

of species change through successive periods.

The pattern of vegetation change may be critical

to understanding how a cultural landscape

evolved as a result of human intervention and

natural disturbances. (See Figure 4.)
P O L L E N , P H Y T O L I T H , A N D M A C R O F L O R A L A N A L Y S E S 7

Macroflora analysis can also contribute to the

reconstruction of a landscape at a particular

period. For example, at Monticello in Virginia,

charcoalified seeds found in the ash of a servant’s

kitchen fireplace on Mulberry Row were identified as sorghum, watermelon, corn, peaches, and

pokeberry. Here, macroflora analysis indicated

some of the crops grown on the farm during

Thomas Jefferson’s occupation, and also contributed dietary information.

In New England, more general changes in

vegetation over the past 2,000 years are being

investigated using the record of macroflora and

pollen deposited in lake beds in central Massachusetts. The identification of historically existing

species and the study of vegetation dynamics will

contribute to a land use and fire history.

A very large macroflora analysis was used to

reconstruct the landscape of Pompeii, Italy. In

A.D. 79, Mount Vesuvius erupted, destroying

Pompeii and Heraculaneum. Vegetation incinerated during the eruption was preserved as

charcoalified macroflora under a layer of pumice and ash many meters deep. Much of

Pompeii has been excavated back to the level

of the soil in A.D. 79. At the soil level,

charcoalified roots are excavated and identified,

or concrete casts are made of root cavities,

leading to plant identification by shape or size.

Charcoalified seeds, roots and branches of

olives, peaches, almonds, grapes, and other

woody plants are contributing information to

the reconstruction of formal gardens and

vineyards within the ancient city.

REFERENCES

General References

International Work Group for Paleoethnobotany.

1983. Plants and Ancient Man: Studies in

Paleoethnobotany. In Proceedings of the Sixth

Symposium of the International Work Group for

Paleoethnobotany. Groningen.

Miller, N.F., and K.L. Gleason, eds. 1994. The

Archaeology of Garden and Field. Pennsylvania:

University of Pennsylvania Press, Philadelphia.

Figure 4. Soil samples are collected during an archeological

excavation, organized according to their respective soil strata,

and analyzed for the presence of pollen, phytoliths, and macroflora. San Juan Island National Historical Park. (NPS, 1985)
8 L A N D S C A P E L I N E S

Pearshall, D.M. 1989. Paleoethnobotany: A

Handbook of Procedures. San Diego: Academic

Press.

Pollen Analysis References

Behre, Karl-Ernst. 1980. The Interpretation of

Anthropogenic Indicators in Pollen Diagrams.

Pollen et Spores 23(2): 225-245.

Bruyam, R.B. 1978. Pollen Indicators of Land Use

Change in Southern Connecticut. Quaternary

Research 9: 349-362.

Bryant, V. 1975. Pollen as an Indicator of Prehistoric Diets in Coahuila, Mexico. Bulletin of the

Texas Archaeological Society 46: 87-106.

Bryant, V., and S.A. Hall. 1993. Archaeological

Palynology in the United States: a Critique.

American Anthropology 58: 277-286.

Bryant, V., and R.G. Holloway. 1983. The Role

of Palynology in Archaeology. Advances in Archaeological Method and Theory 6:191-224.

New York: Academic Press.

Cranwell, L.M. 1992. Pollen. McGraw-Hill

Encyclopedia of Science and Technology 14,

120-126. New York: McGraw-Hill.

Dimbleby, G.W. 1985. The Palynology of Archaeological Sites. New York: Academic Press.

Faegri, K. Kaland, P.E. and K. Krzywinski. 1989.

Textbook of Pollen Analysis. New York: John

Wiley and Sons.

Kelso, Gerald K., and Mary C. Beaudry. 1990.

Pollen Analysis and Urban Land Use: The

Environs of Scottow’s Dock in the 17th, 18th,

and Early 19th-Century Boston. Historical

Archeology 24(1): 61-81.

Moore, P.D., J.A. Webb, and M.E. Collinson.

1991. Pollen Analysis. London: Blackwell Scientific

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Reinhard, K.J., and Stephen A. Mrozowski. 1986.

Pollen and Parasites: Exploring the Biological

Nexus in Historical Archeology. MASCA Journal

4(1): 31-36.

Schoenwetter, James. 1963. Survey of Palynological Results. American Bottom Archeology, Second

Annual Report. Edited by M. L. Fowler. Illinois

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________. 1973. Archeological Pollen Analysis of

Sediment Samples from Asto Village Sites. Les

Etablissements Asto a l’ Epoque Prehispanique.

D. Lavalle and M. Julien. Travaux de l’ Institut

Francais d’ Etudes Andines, 15, Lima.

Solomon, A.M., and D.F. Kroener. 1971. Suburban Replacement of Rural Land Uses Reflected in

the Pollen Rain of Northern New Jersey. New

Jersey Academy of Science Bulletin 16: 30-43.

Phytolith Analysis References

Bozarth, Stephen R. 1987. Diagnostic Opal

Phytoliths from Rinds of Selected Cucurbita

Species. American Antiquity 52(3): 607-15.
P O L L E N , P H Y T O L I T H , A N D M A C R O F L O R A L A N A L Y S E S 9

________. 1990. Diagnostic Opal Phytoliths

from Pods of Selected Varieties of Common

Beans (Phaseolus vulgaris). American Antiquity

55(1): 98-104.

________. 1992. Classification of Opal Phytoliths

Formed in Selected Dicotyledons Native to the

Great Plains. Phytolith Systematics: Emerging

Issues, 193-214. Edited by G. Rapp, Jr. and S.C.

Mulholland. New York: Plenum Press.

Brown, Dwight A. 1984. Prospects and Limits of

a Phytolith Key for Grasses in the Central United

States. Journal of Archeological Science 11(4):

345-368.

Cummings, Linda S. 1992. Illustrated Phytoliths

from Assorted Food Plants. Phytolith Systematics: Emerging Issues, 175-192. Edited by G.

Rapp, Jr. and S.C. Mulholland. New York:

Plenum Press.

Geis, James W. 1973. Biogenic Silica in Selected

Species of Deciduous Angiosperms. Soil Science

116(2): 113-119.

Klein, Robert L., and James W. Geis. 1978. Biogenic

Silica in the Pinaceae. Soil Science 126(3): 145-156.

Kondo, Renzo. 1974. Opal Phytoliths—The

Relations Between the Morphological Features of

Opal Phytoliths and the Taxonomic Groups of

Gramineous Plants. Pedorojisuto (Pedologist) 18:

2-10.

________. 1976. On the Opal Phytoliths of Tree

Origins. Pedorojisuto (Pedologist) 20: 176-190.

________. 1977. Opal Phytoliths, Inorganic,

Biogenic Particles in Plants and Soils. Japan Agricultural Research Quarterly 11(4): 198-203.

Kondo, Renzo, and Tomoko Peason. 1981. Opal

Phytoliths in Tree Leaves (Part 2): Opal Phytoliths

in Dicotyledonous Angiosperm Tree Leaves.

Research Bulletin of Obihiro University, Series 1,

12(3): 217-30.

Kondo, Renzo, and Takahashi Sase. 1986. Opal

Phytoliths, Their Nature and Application. Daiyonki

Kenkyu (Quaternary Research) 25(1): 31-63.

Kondo, Renzo, Takahashi Sase, and Y. Kato. 1987.

Opal Phytolith Analysis of Andisols with Regard to

Interpretation of Paleovegetation. In Proceedings of

the Ninth International Soil Classification Workshop, Japan. 520-534. Edited by D. I. Kinloch et al.

Kondo, Renzo, and T. Sumida. 1978. The Study

of Opal Phytoliths of Tree Leaves I. Opal

Phytoliths in Gymnosperm and Monocotyledonous Angiosperm Tree Leaves. Journal of the

Science of Soil and Manure, Japan 49(2): 138-44.

Parry, D. Wynn, and Frank Smithson. 1958.

Silification of Bulliform Cells in Grasses. Nature

181: 1549-1550.

Piperno, Dolores, R. 1988. Phytolith Analysis: an

Archeological and Geological Perspective. San

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Rovner, Irwin. 1971. Potential of Opal Phytoliths

for Use in Paleoecological Reconstruction. Quaternary Research (1)3: 345-359.
10 L A N D S C A P E L I N E S

________. 1972. Note on a Safer Procedure for

Opal Phytolith Extraction. Quaternary Research

(2)4: 591.

________. 1983. Major Advances in

Archeobotany: Archeological Uses of Opal

Phytolith Analysis. Advances in Archeological

Method and Theory. Vol. 6. Edited by Michael

Schiffer. New York: Academic Press.

________. 1988. Micro- and Macro-environmental Reconstruction Using Plant Opal Phytolith

Data from Archeological Sediments.

Geoarcheology 3(2): 155-165.

________. 1990. Fine-tuning Floral History with

Opal Phytolith Analysis. Earth Patterns, Essays in

Landscape Archeology, 297-308. Edited by

William Kelso and Rachel Most. Charlottesville:

The University Press of Virginia.

Twiss, Page C., Erwin Suess, and Robert M.

Smith. 1969. Morphological Classification of

Grass Phytoliths. In Soil Science Society of

America Proceedings 33(1): 109-115.

Macroflora Analysis References

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Plants Cultivated in the United States and

Canada. Compiled by Liberty Hyde and Zoe

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Bell Site. Wisconsin Archeologist 44(1): 70-71.

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P O L L E N , P H Y T O L I T H , A N D M A C R O F L O R A L A N A L Y S E S 11

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________. 1985. The Use of Plant Food in

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