iid, pyriform, ■ 66 — 120 [i". M. A. Hi »wi in 



Buil. I. ub \X\I\ 



ol Dr. Howe's excelleni description. The species is 

 •in and and though it may generally be recognised by the 



moniliform chai :Is frond-filaments, yel even in tin-se filaments there is 



variation, viz., in diameter, acropetal tapering, terminal branching, degree of con- 

 n the bead-like swellings, shape <>f these swellings (whether nearlj spherical <t 

 ellips mr of filanv Indeed there maj often be a puzzling variability in one and the 



same plant. It is difficuli on the one hand to define the limits of the species, and ontheotherto 

 divid< r>to readily recognised forms. Dr. Howe, who has handled innumerable living 



in the West Indies, writes as follows: "one extreme is represented l>y plants with 

 rbicular flabellum (reniform-cordate when young), reaching a width of 25 cm., supported 

 -\'\ a cylindrical stipe, which has a maximum length, so far as observed, ol 16 cm., tliis 

 "springing from a strongly developed rhizome; the other extreme has a cuneiform flabellum, 

 "sometimes no more than 1 — 2 cm. wide, tapering gradually to a flattened scarcely recognizable 

 "sti|ic. witli rhizome poorly developed. Between these two extremes there seems to be a 

 "nearly perfect series of intermediates ... ." (op. cit. XXXII. 1905. p. 568). Both these extremes 

 are included in his specific description given above. But more recently he has applied the name 

 of forma fulva to the second extreme (the cuneate form) and issued specimens with a description 

 in Collins, Holden and Setchell's Phycotheca Boreali-Americana under no. 1 480. The descrip- 

 tion runs as follows : — 



Ivrainvillea nigricans fulva M. .\. Howe, forma nova. Differs from the typical form 



•icans in its thicker more spongiose and usually more cuneate flabellum. in its flatter, 



"broader, less differentiated stipe. and in the firmer- walled, usually coarser though often more 



"tapering filaments, which are less regularly moniliform, often more tortuous or zig-zag, more 



[uently and more divaricatelj dichotomous, and nearly always yellow or yellowish brown 



rather than fuscous at maturity. 



"Common in 3 — to dm. of, water, inside a reef. Castle Island, Bahamas, Dec. 22. 1907. 



"New York Botanica! Garden Expedition to the Bahamas, collected by Marshall A. Howe. 



- Ihe present form is rather common in the West Indies and by a certain combination 



racters is thus far readily distinguishable from the typical . /. nigricans, in association 



"with which it sometimes grows, yet it seems difficult to point out any one character l>y 



"which it ma) be always recognized, or even any combination of characters which can be 



Eficiently precise terms for specific distinction. The Jamaican plant oi which 



sporangia were recentlj described and figured (Buil. Torr. Bot. Club, vol. 



"XXIV, 7. pi. XXVIII, figs. 8 — 25, 1907) belongs to forma fulva and the form 



i in our previous descriptions of the extremely variable . /. nigricans (Buil. 



XXXII. p. 568, 1905; vol. XXXIV, p. 508, 1907 

 tish Museum is .1 bottle of spiril nens collected in Morne Rouge Bay, 



VV. R. Elliott, which answer to Mr. Howe's description of f. fulva as 



