464 PuLYilORPHISM A\D LIFE-UISTORY IN THE DESMIDIACE^, 



Vol. X., No.2, Feb., 1889, and Vol. x., No.4, April, 1889. Also^. 

 A. M. Edwards, " On ' species ' in tlie Desmidiacese," ibid, VoL 

 XV., 1894.* Unfoitunately I have not seen these contributions 

 to the subject. 



Polymorphism of Doc. trabecula(lihr.). 



There is not the slightest doubt, in my mind, that Doc. Ehren- 

 berr/ii, trihncatum, creniilatum{F\oy & Bisset), 7/m,xiwMm(Reinsch), 

 coronatum, Archerii{J)e\'^.), Indicum(^Gr\xn.), baculoides{^oy it 

 Bisset), nodulosum, phceode'nnum{iicha,a.r.), 6'eor(/ic?t//*(Lagerh.), 

 SHbffeor(/icu7n{CushnvAu), mamobriumlW . & G. S. West), and even- 

 bncuhcni are all growth-variations of one and the same species, 

 which, by the accident of priority, must be called Doc. trabecula. 

 This may appear a large order, but in truth these forms never 

 .should have been accorded specific rank in the first instance. A 

 comparative study of these forms soon compels the conclusion 

 that they are all one. Accordijig to Turner(Alg. E. India, p. 38), 

 Ehrenberg recognised several of them as forms of his Doc. tra- 

 becula; he cites Infusoria, T.vi., f.ii. Is it possible also to scan 

 the excellent figures in Delponte(T.xix.) without admitting Doc. 

 nodulosiim as a variation of Doc. irabeculal In fig.3, nodulosiini 

 and truncalnm are seen as semicells; and fig. 10, which, if 

 magnified 416 diameters, is a good illustration of Doc. trabecida,. 

 would at the lesser magnification be considered a form of fi".2 

 i.e., of D. 'iiodidotiitm. Compare, too, the figures of trabecula 

 (PI. XXX., figs. 12, 13) with those of maxivnimCPl xxxi,, figs. 1,2) iir 

 W. ik G. S. West's Monog. Brit. Desm.( Vol.i.). Fig.l of maxi- 

 tnwu has even the double basal inflations which seem to be char- 

 acteristic of European forms of Elirenhergii; so also has the figure 

 of trabecida in Pl.xxx., f. 11. 



* Consult also G. S. West, "Variation in the DesmidieaB," Journ. 

 Linn. Soc, Bot., xxxiv., 1899; W. Schmidle, " Ueber die individuelle 

 Variabilitut einer Cosmaiienspecies," Hedwigia, 1893, Heft 3; 0. Borge, 

 "Ueber die Variabilitjit der Desmidiaceen," Ofveis. af K. Sv. Yet.-Akad, 

 Fiirh., 1890, No.4; and J. Liitkemiiller, " Beob. iiber die Chlorophyllkorijer 

 einig. Desmid." Oesterr. botan. Zeitschiift, xHii., 1893, No.l. 



