KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 



39 



East India, ex Utricularia fasciculata, G. v. L. 



I think that this sp. is correctly placed by Delponte among the Docidia, it can 

 hardly be a Penium as it possesses a decided basal inflation. 



I have purposely retained the Docidia under their old generic appellation, not only 

 as a question of priority, but I imagine that sooner or låter the name Pleurotcenium of 

 Xägeli will be discarded. As before stated, I deem it quite as reasonable to classify 

 solely by form, as to make attempts at classification in which form and cell-contents both 

 plav a curiously commingled part. Lundell, to whom the acknowledgments of Algo- 

 logists are dne for so highly adding to our knowledge, divides the present genus into 

 Docidium (without apical vesicles, and having axillary chlorophyll) and Pleurotcenium 

 emend. (with apical vesicles and laminar chlorophyll). His tirst example is Doe. baculum 

 Bréb., of which Ralfs, Br. Desm. t. XXXIII, f. 5 a (indistinctly) and Delponte, Desm. 

 subalp. t. XX, f. 15, 16 (distinetly) give figures with 'loeelli' at the apices! As I have seen 

 English specimens of this plant both with and without apical vesicles, I have considered 

 them as a sign of age or state (vet unknown) of the Desmid; and, like Wallich, I find 

 their presence to be somewhat inconstant. In young and undeveloped specimens the ab- 

 sence of vesicles is not unexpected, but it is verv puzzling to account for their frequent 

 absence in fully developed fronds. Cfr Archer in Proc. Dubl. Micr. Club, Q. J. Mic. Sci., 

 p. 26*2, 1865; and p. 121, 1866. For a form-classincation of Docidia, I suggest the 

 following subgenera: 

 A. Orthidium (oodog, = rectus; fdtog = sui generis). 



Cellulis lrevibus, punctatis vel granulatis. 



Typ. sp. Doe. truncatum, Ehrenbergii, sceptrum 

 K ii t i il i ii in (<Jt'T/d/ooj = corrugo; etc). 



Cellulis plus minus rugosis. 



Typ. sp. D. verrucosum, salebrosum. 

 Ha ni mat id i ii ni (äuua = nodus; etc). 



Cellulis nodibus instructis; sectio stellatis. 



Typ. sp. Doe nodosum. 

 < Kil <• mal iil i ii ni (pTdijjua = tumör; etc). 



Cellulas tumöres ferentes; sectio circulares. 



Typ. sp. D. undulatum, Burmense. 

 Oontidium {ooov = ovum; etc). 



Semicellulis plus minus ovatis. 



Typ. sp. D. ovatum, pyriforme. 

 A classification of Pleurotcenium (excl. Docidium) has been proposed by Raciborski, 

 Desm. Nov. p. 35, 1889, the foundation of which is the based aspect of the semicell. In 

 this he unites A, B and E, supra, under Pleurotcenium, Näg.; C under Docidiopsis ejus, 

 while Triploceras Bail. forms his third sub-genus, his definition of which is only framed 

 to include the tumid and verticillate species, and not such a plant as T. abbreviatum, Xor.; 

 D. undulatum Bail. (as D. nobile Richt.) he plaoes under Docidium, 1. c. p. 3. Hence, 

 if Dr. Raciborski intended to classify liv basal aspect only. he should have included the 



B 



Lateribus fere rectis, vel leniter 

 curvatis. 



D 



E 



Lateribus undulatis vel nodiferis. 



Lateribus valde curvatis. 



