13 



1. Chlorodesmis Bailey and Harvey 

 (Figs. 69—75). 



Harvey Nereis Boreali-Americana Part III. in Smithsonian Contributions to Knowledge, X. 

 (1858) p. 29; Bail. & Harv. in Wilkes U. S. Explor. Exped. XVII. Bot. 1862, p. 172, 

 Algae tab. VIII, figs. 8— to; J. G. Agardh Till Alg. Syst. V. 1887. p. 48 (pro parte); 

 De Toni Syll. Alg. 1. 1889 pp. 439, 513; Engler und Prantl Die natürlichen Pflanzen- 

 familien I. 2. 1S90. p. 141. 



Mature plant usually felted at base so as often to form a colourless spurious stipes, 

 and bearing above a radiating penicilloid tuft of free, green, uncalcified, straight, filaments; 

 filaments in their lower part more or less constricted at irregular intervals, branched at short 

 intervals, radicelliferous and colourless; in their upper part cylindrical, green, flaccid, dichoto- 

 mously branched at longer intervals, constricted at the base of the branches. 



This genus was founded upon C. comosa, which was first collected in the Fiji Islands 

 by the United States Exploring Expedition of 1838 — 42 under Captain Wilkes. It was recog- 

 nised by Bailey and Harvey as a distinct genus, and the official diagnosis was published in 

 their report (loc. cit. 1S62 p. 172). But before this official report appeared, Harvey described 

 the genus in his Nereis Bor.-Amer. in 1S5S (loc. cit.) in order to include a doubtful species 

 from the West Indies, C. vaucheriaeformis, which has since been transferred to Derbesia by 

 Prof. Farlow. Harvey had in the meantime himself visited the Friendly Islands, and there 

 collected C. coi?iosa abundantly on all the coral reefs, where he says, it forms a very striking 

 object on the extreme outer edge of the reef. 



In 1874, Zanardini described C. major collected by Fullagar and Lixd in Lord Howe 

 Island, and pointed out that it has filaments twice as thick as those of C. comosa. We have 

 never seen Zaxardini's species. 



In 1880, Kjellman published a description of his C. pachypus in Bot. Xotiser, 1880, 

 p. 117; he had himself collected the specimens of it at Labuan in Borneo, and issued samples 

 under n° 343 in Wittrock and Xordstedt's Algae Exsiccatae. Kjellman's species was trans- 

 ferred to Avrainvillea papitana by Murray and Boodle in Journal of Botany XXVII, 1889, 

 p. 71. A. papnana is synonymous with our A. crccta (p. 29; see also p. 31). 



J. G. Agardh (loc. cit. p. 49) added another species, C. caespitosa (Ceylon, Ferguson 

 n" 110), which in our opinion constitutes a separate genus, namely, Rhipidodesmis (see p. 62). 



In 1889, Murray and Boodle (loc. cit. pp. 71, 72) transferred C. comosa and C. caespi- 

 tosa to Avrainvillea contending that the former species "seems to stand in much the same 

 relation to Avrainvillea as the Espera form does to Paiicillus'. They argue (loc. cit. p. 68) 

 that C. comosa "is merely an Avrainvillea with the filaments free, instead of interwoven, and 

 the rhizoid mass probably broken off short"; and they call attention to "other forms exactly 

 resembling Chlorodesmis (Ferguson 's n" 290) which "are young growth forms connected by 

 an unbroken series with mature forms of Avrainvillea - - in this case A. papnana' '. We have 

 examined Ferguson 's series of specimens (Ceylon n" 290) illustrating the stages of growth of 

 A. papnana, and we are unable to find sufficiënt likeness between its young forms and the 



