V. WRANGELIACE^. 143 



happens that the ramclli are longer at one side of the stem than at tlie other, the 

 long and short filaments alternating from node to node. 



The sporiferous-mtdeiis generally terminates a short branch. It is destitute of 

 any proper coating or pericarp, but is surrounded and often closely invested by a 

 whorl of byssoid ramelli. It consists of a tuft of spore-threads, radiating from the 

 apex of the branch, and bearing terminal, pear-shayed spores. The tetmsporef; are 

 scattered along the ramelli, of whose metamorphosed branches they are formed ; 

 they are spherical or ellipsoidal, sessile, and triangularly divided. 



Of this genus, which was originally founded on our W. penicillata, several species 

 are now known, dispersed through the Atlantic and Southern Oceans. Some of 

 them have the external habit of Grij/ithia, others of Callifliamnion, and others of 

 Dasya, genera to which, in their fructification, they have but little aifinity. In 

 the nature and position of the tetraspores, indeed, there is a close resemblance be- 

 tween Wranr/eUa and CalUthamnion ; but the structure of the sporiferous-nucleus 

 obliges us to place them widely apart. From Dasya the monosiphonous frond 

 affords an easily-seen distinction, independently of fructification. 



1. V^nk^GELW penmllata, kg. ; frond ultra-setaceous, decompound-pinnate, dis- 

 tichous, the stem and larger branches corticate, opaque, the lesser branches articu- 

 late ; ramelli whorled round the nodes, repeatedly dichotomous, of nearly equal 

 diameter throughout, obtuse, their articulations contracted at the dissepiments, 

 4 — 8 times as long as broad. J. Ag. Sp. Alg. 2, p. 708. Kiitz. Sp. Alg. p. 6(54. 

 (Tab. XXXIV. B.) 



Hab. Key West, very abundant. W. H. //., Dr. Blodgett, Prof. Tuomey, &c. 

 (vv.) 



A most variable plant in aspect, according to the greater or less development of 

 the primary and secondary branches ; but when this is borne in mind, easily recog- 

 nisable under all its forms. The branching is uniformly distichous, and decom- 

 pound-pinnate. Sometimes it is nearly simply pinnate, with few and distant pinna; ; 

 sometimes a few alternate long branches, or primary pinnaj, are set with minute 

 alternate pinnules 2 or 3 lines long ; sometimes the frond is closely and regularly 

 thrice or four times pinnated, each branch having an ovate or lanceolate outline 

 and fern-like aspect ; and between these extreme forms there are endless varieties. 

 In all cases the branches are whorled at every node with very soft, repeatedly 

 dichotomous, confervoid filaments, which are very frequently longer at one side of 

 the branch than at the other. The articulations of these ramelli are 4 to 6 or 8 

 times as long as broad, swollen upwards, the dissepiments much contracted, and 

 the terminal cell ol)tuse. The stem and larger branches are coated with small 

 cellules, and thus appear opaque and inarticulate ; in the smaller branches the 

 cellular coat is less uniformly spread, and the ultimate or youngest branches are 

 pellucidly articulate. The f<poriferotis mideus is globose, and usually terminates 

 the shorter branches. It is surrounded by an involucre composed of copious 



