522 RHODOMELACEAE. 



rencia, Halimeda, and other algae, growing near the low-water mark, as at 

 Hungry Say. Its main axes have 5 or 6 pericentral siphons, its often short, 

 divaricate, subulate or spinescent branchlets sometimes have only 4, and its 

 tetrasporic branches often 7 or 8. The segments of the main axes are about 

 as long as broad, sometimes longer, sometimes shorter, while those of the 

 branches are commonly shorter than broad. The branches are 4-ranked, 

 though occasionally they may have an illusory appearance of being 2-ranked. 

 The branches, however, occur in alternating pairs, of which the more ventral 

 of each pair becomes a ramified ''long" branch, while the more dorsal of each 

 pair becomes a simple ''short" branch, in which respect Dipterosiphonia 

 differs from Herposiphonia and Lophosiphonia. In the present species, as 

 noted by Falkenberg, this regularity is often not manifest on account of the 

 slight development of the "long" branches. In the free parts, also, the 

 branches are only sparingly developed and their relations are obscure, but in 

 the younger conditions and in creeping parts, the form and relations of the 

 branches are manifest and the plant is a typical Dipterosiphonia. 



Falkenbergia Hillebrandii (Born.) Falkenb. may be recognized by its 

 having only 3 pericentral siphons, the siphons of one segment usually alternat- 

 ing regularly with the siphons of the next. The filaments are very slender, 

 delicate, and flaccid and adhere firmly to paper on drying. The color is a 

 reddish purple, tending sometimes to rose and sometimes to brown. The 

 branching is lateral or pseudodichotomous. Not uncommon on other algae, 

 sticks, etc., occurring particularly in association with mangroves and in the 

 ponds of the Walsingham region. (Phyc. Bor.-Am. 2043.) 



Wrightiella Blodgettii (Harv.) Schmitz, is of occasional occurrence near 

 low-water mark, as at Harris Bay and elsewhere along the Sx)uth Shore. It is 

 confmonly 4^7 inches high, with a few plumose main axes that have the 

 appearance of being distichously pinnate when dried and pressed, though the 

 branches and branchlets are in reality spirally alternate in four ranks. The 

 numerous short branches are mostly about I inch long and are beset with 

 minute conic or awl-shaped ramull that are visible with a hand-lens. Fila- 

 mentous monosiphonous branchlets that soon fall off also occur, alternating 

 with the stouter ones. Except for these the plant is corticated throughout, a 

 section showing four pericentral siphons. The tetraspores occur on the mono- 

 siphous branchlets. The cystocarps are short-stalked and urceolate and are 

 conspicuous when present. (Phyc. Bor.-Am. 1942.) 



Wrightiella Tumanowiczi (Gatty) Schmitz. The types of both this 

 species and the preceding came from Key West, Florida, where the two differ 

 rather markedly in habit, W. Tumanowiczi being more flaccid, having more 

 persistent monosiphonous branchlets and being almost destitute of the short 

 branches (about I inch long) that are responsible for the distichous-pinnate 

 appearance of the main branches of dried specimens of W. Blodgettii. TV. 

 Tumanowiczi resembles slender conditions of Dasya pedicellata, while TV. 

 Blodgettii is slightly suggestive of lax forms of Bryothamnion Seaforthii. 

 Under a microscope the texture of TV. Tumanoiviczi is rather more translucent 



