THE CEYLON SPECIES OP CAULERPA. 119 



can be seen from fig. 12. They are narrow, weak, and covered in all their length with small three-sided 

 branchlets or pinnules. By their weakness, and by the fact that they are covered in all their length with 

 three-sided pinnules, these branches differ from those with three three-sided pinnules only at the base 

 in the plant fiom the pearl-banks. The peculiar transition form wliich Ferguson collected at Tuticorin, 

 and which is of great interest owing to the construction of its shoots, I call /. tuticorinensis. The nature 

 of this kind of shoots, etc., I have already discussed before in the general part of this work, and I will 

 only emphasize in this place that I am not of opinion that the classification of this form under Lessonii 

 as the main species must necessarily be so explained that /. tuticorinensis is subordinate to Lessonii /. 

 typica. I have only wished in this manner to point out their close genetic relationship. 



I think, therefore, that I have shown that Bory's C. Lessonii, described and figured as early as 

 1828, must be retained as at least relatively a weU-characterized form. The nenne fissidentoides (Grev.) 

 from the year 1853 must therefore be placed in the list of synonyms. And in my opinion we should 

 also refer C. pennata (J. G. Agardh) from 1872 to the same Ust. The type-specimens (Herb. J. G. Agardh 

 No. 16,624) which served Agardh as the material for his description, are evidently smaller forms of the 

 same species I have figured in fig. 11. Such weaker branches are also to be foimd among the material of 

 C. Lessonii collected by Hoknell. But then Agardh's C. pennata is of the very same coarse structure 

 as C. Lessonii and with rather broad main axes. Agardh, also, in the diagnosis speaks about "rachis 

 atiuscula," just as he says about the plant that is it " robustior." To avoid confusion one must remember 

 that Agardh's specimens are, as he himself expressly pointed out (Till. Alg. Syst. I., p. 26) mixed with 

 C. sertularioides {= C. plumaris (Forsk.). It follows as a matter of course that C. plumulifera, according 

 to Weber v. Bosse's definition, must also be ranged among the synonyms. If Zanardini's specimens 

 should also be included is an open question, as I have not had an opportunity of examining Zanardini's 

 type-specimens. 



That C. Lessonii is closely related to C. cupressoides is beyond a doubt. Especially the broader 

 forms among the lycopodium series are very similar to C. Lessonii, and I have been veiy doubtful about /. 

 amicorum in particular, as it offers great resemblance to Lessonii. It seems to me not improbable that 

 perhaps several of these forms classed by Weber v. Bosse among the comprehensive G. cv/pressoides 

 might with equal reason be transferred to the Lessonii group. This may also apply to some C. Freycinetii 

 V. pedinata forms. For as Weber v. Bosse writes {loc. cii. p. 316) about this plant : " Souvent une partie 

 de la fronde, ou des frondes entieres, portent de petits ramules opposes, pectines, presqm, aussi grand que 

 ceux du Lessonii. * Ces echantillons portent dans les livres et la collection de MAzii et Schramm les noms 

 errones de C. pectinata, KuTZ ou de C. Lessonii, Bory." 



But it is precisely the occurrence of large broad shoot branches with opposite pinnules that seems 

 to refer these forms rather to Lessonii than to Freycinetii. As for these forms belonging to the Thtiyoideae 

 series, itisof more importance that a critical study of them be made in their natural habitat, cowibined 

 with experimental cultures, and of their geographical distribution, than of perhaps any other Caulerpas, 

 in order to get an insight into the principles governing the variation of these plants, which is necessary 

 as a basis for their taxonomy. 



In this connection we may point out that this Ferguson's C. A. 413, according to notes in the 

 Peradeniya Herbarium, was collected by him at Tuticorin in S. India, and consequently does not really 

 belong to the Ceylon flora. But as all the algae collected by Ferguson at Tuticorin have been distributed 

 in the collection " Ferguson, Ceylon Algae," it is expUcable that several forms have been mentioned in 

 literature as being from Ceylon, although, strictly speaking, they have not been found there. For reasons 

 mentioned in my introduction, they are more conveniently dealt with in connection with the Ceylon 

 marine vegetation in general, though not belonging to the flora of Ceylon in a strict pohtico -geographical 

 <:-n3e. 



* Italicised by tlie present author. 



