MARINE Al,GM OF BEAUFORT, N. C. 505 



pectinate, older ones corymbose above, virgate and beset with short thornlike branchlets below, grad- 

 ually tapering and more or less divided into fine branchlets toward the apices, branchlets more or less 

 subulate, often compound, arising in clusters over a considerable portion of the frond or especially 

 toward the apices; pericentral cells 8 to 20, usually 16, segments i to 4 diameters long, usually i to 1.5 

 diameters, upper and lower ones shorter, no cortex over most of the frond, but sometimes with a thin 

 cortex over the older portions; tetrasporangia forming wartlike swellings in the distorted branchlets; 

 antheridia very long, elliptical, often curved; cystocarps broad-ovate; color dark brownish purple. 



Warm and temperate North Atlantic. 



Beaufort, N. C. : Fairly abundant on Fort Macon and Shackleford jetties, May, 1907 ; fairly abundant 

 all over harbor, abundant on Fort Macon jetties, very abundant on Shackleford jetties, and fairly abund- 

 ant on Bogue Beach, April, 1908, fruiting. 



This is an exceedingly variable species, many forms having been described. The habit may be 

 robust with branchlets borne in close pectinate series throughout the frond, or more slender, with the 

 branches more elongated and the branchlets borne in close tufts, especially toward the apices. Usually 

 the branchlets are broken off from the lower parts of the frond, and the remnants of these remain as 

 short, thornlike processes. Often the apices are very finely divided, forming dense, wedge-shaped 

 tufts. Many of these differences seem to depend on the size and age of the plant. 



The Beaufort plants have a loose habit, with regular, alternate, pinnate branches, beset below with 

 short thornlike processes, and bearing branchlets in not very dense tufts toward their apices. 



This is the only species observed in this region with as many as 16 pericentral cells. In spite of 

 the variations, the determination is not very difficult. It is the only species of the genus so far found 

 at Beaufort during the spring. 



Since the identity of Conferva nigrescent Hudson is doubtful, it is questionable whether this species 

 should be called P. nigrescens or P.fucoides, a specific name applied by Hudson to what is undoubtedly 

 the present species. It has, however, seemed proper to keep the current name until it can be clearly 

 shown that this should be changed. 



Besides the plants mentioned above, numerous indeterminable small specimens and 

 fragments belonging to this genus have been found at Fort Macon and Shackleford, on 

 buoys, on Bogue Beach, in a tide pool at Fort Macon, and in the harbor, growing 

 on jetties, buoys, shells, other algae, or animals, or floating free. Some of these resem- 

 bled P. harueyi, some resembled P. denudata, while some were too small or too frag- 

 mentary to be related to any species. During July and August, 1904, broken fragments 

 of a species with four pericentral cells formed large masses along Bogue Beach and 

 covering the bottom within the inlet at Fort Macon, being the predominant form found 

 there at that time. In December, 1908, tetrasporic specimens 1.5 to 4 cm. tall were 

 collected on Fort Macon jetty, with fine capillary filaments, somewhat dichotomously 

 branched, having four to six pericentral cells. Fruiting specimens about 2 cm. tall, 

 apparently having seven pericentral cells, were found at Pawleys Island near George- 

 town, S. C., August, 1909. 



Genus 4. Brongniartella Bory. 

 Brongniartella, Bory, in Dictionnaire classique d'hjstoire naturelle, tome 2, p. 516. 1822. 



Frond erect, terete, radially constructed, usually laterally, sometimes dichtomously, 

 branched; structure cellular or filamentous-cellular, with a single circle of five or seven 

 (rarely four) pericentral cells, naked or sooner or later surrounded by a dense rhizoidal 

 cortex, apical growth monopodial, apical cell transversely divided, the entire frond or 

 the younger parts densely covered by spirally arranged, usually more or less dichotomous, 

 colored trichoblasts, lateral branches arising from the basal cells of trichoblasts, forming 

 elongated, vegetative branches or transformed into short, fruiting branches; tetra- 

 sporangia numerous, occurring singly in spiral rows in more or less transformed branch- 

 lets, triangularly divided; antheridia, procarps, and cystocarps as in Polysiphonia. 



About eight species, in warm seas. 



