Alt. A I.-). J 



I EK \Ml.\i I..1.. 





■ \ 



ORDEH IV. CEttAMlACE I H 



I I .1 I r | ./ | . 



■ 



Diagnosis. • • or tubular unaymmctn 



Seaweed] e or purplish colour, seldom olive or violet Their i 



tubular, or round and short, or polj gonal ; Bometimi ■ .1 in a &ing) ( 



tiniee disposed in 



|ual length, forming an articuhtl 

 sometimes in several row 

 li ngth, when the) constitute a cellular fi 

 'I he propagation b) meaiu 

 also Sphaerospores and Tetras] 

 in fours (or threes), within a transpai 

 spore, or mother cell, and collected in I 

 of many different forms and truck 



The subdivision ol the reproductn 

 or U traspores into four, or 

 particles, is tl tural 



order, and :it once distinguishes it from the 

 rest im the alliance. M. Decaisne i 

 Btress upon this point, first used byhimsell 

 for systematical purposes, and be 

 quite a secondary value to the various n 

 in whirl; Mich Bpores are group rank 



those modi a more highrj 

 ili mud at mi- foult d 

 plug haute valeur a Kth\ qui »'a 



-/»• U | It is, however, a v< rj Btrik 



thi Rosetangles, that they Bhould have so much l a variety of fructification 



than their allies, and this, in connection with the quaternary structure of I 

 seems to in. licat.- their being the highest form of the Algal alliance. 



Although the subdivision of the spores 

 I-. four is of uniform occurrenci among 

 these plants, yet it takes place indifferent 

 ways, and is subject to certain modifica- 

 tions, concerning which the languagi ML 

 Decaisne is instructive. " 1 have shewn," 

 he says, "in another place, that the sphsero- 

 spon 3, or quaternary reproductive bodies, 

 which M. Klitzing has perhaps better 

 called Tetraspores, offer three modifica- 

 Thej are either little Bpheres, 

 which divide into four wedge-shaped par- 

 ticles with a round baa D i . I 

 ramium, &c.) ; ox oblong bodies, which 

 ■re cut across into four distinct spores 

 (Hypnea, Catenella, &c.) ; or, finally, ob- 

 long bodies, which divide vertically and 

 transversely, bo as to form segments of 

 cylinders, rounded at one extremity, and 

 truncal, at the other, as iii Peysonnelia. 

 Hie mod< of formation, and the essential 

 Organisation ol these Bpores, is the Bame 

 in each type, whether the tetraspores pro- 

 )< 1 1 li. vi.n 1 die tissue, or arc organised in 

 the interior of the frond. When young, 

 the tetraspores -.-how n i exterior mem- 

 brane, luit appi ar as a reddish spherule, 

 the development ol which may be followed 



l SI 



* !' it the explanation of the terms 





; ■; Griffithsia splia 

 l'u \i — Magnified branch of CoraUlna 

 situ ; :; a tetraspon ; ; I 

 ci:wlu.- cluvaefi rous, showing its i nth 



