BOLDIA: A NEW RHODOPHYCEAN GENUS

Mature thalli of Boldia erythrosiphon gen. et sp. nov. from Big Walker Creek, Giles Co., Va., are hollow, simple, or, rarely, branched tubular cylinders. The plants generally are from 1 to 20 cm in length and 0.1-1.5 cm in diameter, brownish-red or olivaceous in color, and grow singly or in clusters from a multicellular holdfast. The vegetative portion of the thallus is essentially monostromatic, comprised of isodiametric, or slightly elongate, uninucleate cells with numerous parietal, simple or lobed, ribbon-like chromatophore segments. Monospores are produced from narrow, branching filaments (derived from vegetative cells) which form a reticulate pattern in the intercellular matrix external to and at the juncture between groups of (usually 2, 4 or 8) vegetative cells. The spores are liberated singly and germinate into short, branched filaments. New plants arise from small, monostromatic discs of branching filaments united in a common matrix which become cushion-like and ultimately produce saccate thalli. While Boldia shows affinities with certain members of the Bangiales, it cannot be assigned to any of the presently recognized families. Accordingly, it is placed in a new and distinct family, Boldiaceae, distinguished by the unique manner in which asexual spores are produced from filaments derived from vegetative cells, the filaments developing within the intercellular matrix of the thallus, as well as by the parietal chromatophores of the vegetative cells. A MOST unusual freshwater red alga has been found growing in tributaries of the New River in Virginia. The first specimen of this plant was discovered by members of the animal ecology class of the Mountain Lake Biological Station of the University of Virginia, taught by Dr. William S. Woolcott in the summer of 1958. This class, engaged in an icthyological study of local streams, was asked to collect Lemanea for the plant morphology course and, in response, Dr. Woolcott brought to the Laboratory a snail with an attached saccate thallus approximately 3.5 cm in length. While the first inclination was to dismiss it, since its body form was so different from that of any freshwater alga known, after microscopic examination it became clear that it was a red alga with structure so unique that it could not be accommodated in any of the presently recognized familial taxa of this group. Return to the site of the original collection revealed the plant in abundance. The following account of its general morphology is based on the material collected then and in subsequent summers. DIAGNosIs-Boldiaceae famn. nov.-Thallus adultus vegetativus parenchymaticus, cellulis chromatophora parietalia exhibentibus. Monosporae ex filamentis formatae inter cellular vegetativas. Plantae praeterea notas Rhodo1 Received for publication May 25, 1964. The writer is indebted to Mr. Tyge Christensen, Copenhagen University for preparation of the Latin diagnosis and to Professors W. R. Taylor, R. C. Starr and G. F. Papenfuss for their helpful comments. Contribution from the Botanical Laboratory, The University of Tennessee, n. ser 238. phycearum Bangialium praebentes. Genus typificum Boldia infra descriptum. Boldia erythrosiphon gen. et sp. nov.-Thallus saccato-tubularis, simplex vel raro ramificatus, fusco-carneus vel olivaceus, 1-20 cm altus, ad 1.5 cm diam., unicus disco basali affixus vel complures e pulvinari communi hemisphaerico multicellulari emissi, in statu vegetativo vix ulla exceptione monostromaticus. Cellulae isodiametricae vel subelongatae, plerumque 10-20,u diam., quaeque unico nucleo instructa, chromatophoro interdum perjuvenis vel propagationis causa formata unico centrali, praeterea compluribus parietalibus, taeniiformibus, simplicibus vel irregulariter lobatis et ramificatis. Propagatio non-sexualis per sporas peracta e filamentis angustis copiose provenientes sub superficie exteriore thalli penetratibus, parietes cellulas vegetativas contiguas discernentes reticulatim secutis. Sporae in filamentorum cellulis singulae, per poros parietales liberatae, in filamenta brevia ramificata germinantes. Thalli juvenes initio disciformes, monostromatici, e filamentis radiantibus contiguis formati, postea pulvinati, demum in partes saccatas elati. Propagatio sexualis ignota. Typus die 5, Jul. anni 1958 in amne Big Walker Creek regionis Virginianae Giles County (folii quartae Pearisburg) Americae Borealis ab auctore lectus, in honorem Harold C. Bold ob phycologiam ut plantarum morphologiam ingenio excitante communicatam nominatus, in herbario cul nomen U. S. National Herbarium, urbis Washington depositus. [The JOURNAL for May-June (51: 465-573) was issued June 11, 19641 AMERICAN JOURNAL OF BOTANY, Vol. 51: No. 6, 1964