THE CEYLON SPfeCIES OF CAULEI^PA. 99 



different groups : bud variations due to the vegetative cleavage (" Spaltung ") of bastards ; bud varia- 

 tions due to vegetative atavistn in so-called middle races (" Mittelrasseti") ; thirdly, the reial bud 

 variations, which again may be of two kinds, viz., such as afe of atavistic nature and Such as are not 

 of atavistic nature but are progrtessive mutations (vegetative mutations). 



As no other propagation than by shoot formation occurs in the Caulerjias every kind of variation 

 due to bastard formation is, 6i course, absolutely out of the questibh. There remain, consequently, bud 

 atavism and teal mutation. If, now, it is of the former kind, the changes that takis jplace iti the appear- 

 ancie of the shoot must therefore Correspond with those of ancestral forms. Since no absolute certainty 

 can be arrived at in this matter, we must content ourselves with examining whether possibly any now li vino- 

 species normally possesses branches of a kind which in another species iajipfears as bud vai?iation. If so, 

 it would support the supposition that atavistic phenomena are present. 



If we now examine C. sedoides f. mixta (fig. 50) which afforded us an example of such a bud varia- 

 tion, it wiU appear that its elongated or irregulai" branchlets have the very same form or, at least, are 

 very similar to those in C. ambigua, which belongs to thfe same group as C. sedoides (C)f . ihy fig. 50 and 1^1. 

 I., figs. 4, 6, 7, 14 in Okamttra, " On the Alg. of the Ogasawat-a-jima" (Sortin Islands). 



It thus seems by no means improbable that C. sedoides is derived from a species which has been very 

 closely alUed with or similar to C. ambigua. That cylindrical branchlets (= pinnules) are more primitive 

 than spherical ones I have already tried to show in the foregoing, while dealing with the question of 

 relationship between C. racemosa, Icetevirens, and Chemnitzid. In complete analogy with tliis is, too, 

 that such species as C. ambigua must be considered as more primitive than sedoides f. crassicaulis. Every- 

 thing, therefore, points to the conclusion that the bud-variation in C. sedoides f. mixta should be 

 regarded as an atavistic reversion. 



Whether the same is thecase with C. Lessonii f. tuticorinensis is somewhat more difficult to decide. 

 The form which I have indicated as the main species of Lessonii (fig. 11) shows at the base branches 

 with three-sided branchlets ; thus, in conformity with the opinion I have attempted to vindicate, it 

 s derived from a species with three-sided branchlets, i.e., from one of the cwpressoides forms. C. Lessonii 

 f. tuticorinensis (fig. 12) also has the prevalent number of branches of the common cupressoides form ; 

 two-sided as well as three-sided, and the great majority of the branches never have a different appearance. 

 But aniidst these branches the broad flattienied ones with their two-sided branchlets are formed just as 

 bud variations. These are from the very beginning two-sided, and not, as often in Lessonii, three-sided 

 at the base. It is therefore impossible to say that the broad flat branches ih C. Lessonii f. tuticorinensis 

 are reversions to Lessonii, for that would mean that Lessonii, that is the bi-bad flat leaf form, were more 

 primitive than the cupressoides branches. But this is contradicted by G. Lessonii itself, in which the 

 development shows the exact contrary (fig. 11). This does not seem to stipjibrt the atavistic nature of 

 these shoots ; yet it seems impossible to look for any definite solution of this problem at the present time. 

 It may be possible for Lessonii and C. Lessonii f. tuticorinensis to be in the nature of parallel forms of equal 

 rank, both deriving from a cupressoides form and With a tendency to form flat bilateral branches. But 

 in the one {Lessonii) this tendency is the predominant, and has so to speak become the normal one, while 

 in the other one {tuticorinensis) this tendency is more latfellt and only rarely reveals itself. This is of 

 course a pure speculation, and for the solution of this, as of so many similar questions touching 

 variation in Caulerpa, experiments and cultures are necessary which the traveller in the Tropics lias 

 difficulty in arranging. 



That both these forms go together seems to me indisputable, and 1 have wished to give expression 

 to this by calling one form the /. tuticorinensis of the other, Lessonii. But with this I do not imply that 

 Lessonii is necessarily more primitive, for here, as in so many other cases, the first form to be distin- 

 guished becomes the main species, the later ones the variations, though ^vith equally good reason the 

 reverse might have taken place. 



