94 W. B. TUENER, FRESH-WATEB ALG.E OF EAST INDIA. 



agree except in the thickness of membrane, and, as this varies so much aceorcling to 

 the age of the Zygospore, I deera it unimportant. 



16. M. apiculata, (Ehr.) Mengh. (Synops. Desm. p. 216, 1840; Euastrum apiculatum Ehr. 

 Abh. Berl. Ak. p. 245, 1833; Infus. p. 167; 1. c. t, XII, f. 2 E, aculeatum (pro errore); 

 Euastrum spinuligerum Bréb. fide Mengh. 1. c), var. lacerata, n. v. 



Var. quarta parte minor quam f. typica; lobulis laciniate partitis vel laeeratis, 

 irregularibus. Figurae 1, Tab. V (in Desm. sub-alp.), Delpontii paullulum accedens. 



Long. et lat. 185, lat. isth. 30, lat. apic. 84, lat, lob. pol. 44 u. T. XXII, f. 3. 



The interiör lobes somewhat reserable the sub-alpine form; the polar lobe is more 

 like that of the English plant; cfr my fig. in Cooke's Br. Desm. t. 48 a b (non c- 

 which is after Delp. 1. c. f. 2). 



Khasia, ex ntriculariis, G. von L. comm. 



Dr. Nordstedt (Desm. Bornh. pp. 187 — 90 et 212) propounds an ingenious 

 theory that the plants described as M. fimbriata Ralfs (Br. Desm. p. 71, t. VIII, f. 2); 

 idem v. omata Bulnheim (Hedw. II, p. 21, t. II, f. 3, 1859); iderri (sub nomine M- 

 aculeata) Rostock in Rabh. Alg. Europ. No. 1856; Hedw. II, p. 59; M. brachyptera 

 Lund. (Desm. Suec. p. 12, t, I, f. 4); M. ffalis Racib. (Desm. Polon. p. 40, t, V (XIV), 

 f. 1); with certain forms of these, are but varieties and forms of the above species. 

 I would remark that not only is the retention of some of these as species a matter 

 of scientific convenience, but the correctness of their proposed fusion is only con- 

 jectural, their respective zygospores being unknown; it therefore seems inexpedient to 

 change their status under existing knowledge of them. As to Bulnheim's and Rostocks 

 varieties (and Al. Halts also?) it seems probable that they do naturally fall under this 

 species, but with respect to Al. fimbriata and M. brachyptera, although no doubt they 

 are allies of Ehrenberg's plant, it seems to me that they should continue to retain 

 their specific rank. 



17. M. foliacea, Bailey (in Ralfs Br. Desm. p. 210, t, XXXV, f. 3; Wallich Desm. Beng. 

 p. 2 HO). Formae duae: 



«. typica. Fröns lata vel latior quam longa. T. VI, f. 12 — 14. 

 (i. eloiigata. Fröns longior quam lata (var. />' Wallich, 1. c. t, XI\ r , f. I). 

 Dimensiones: 



Long. lat. lat. isth. lat. apic. lat. lob. pol. crass. 



« 70—73 72—78 12—14 30—32 10—12 12 //. 



Ii 85—90 70—75 11—13 32 15 



Wallich » 85 72 — — » 



The type alone appears in Wallichs Mscr. of 1855 (Nos. 70, 85, 88), under 

 the name Micrasterias armilla; it seems that his figure in Beng. Desm. was drawn 

 from the otlier form. Wallich states that in the young zygospore the spines are 

 simply conico-aculeate; in the mature zygospore they are bi- or tri-furcate at their 

 apices. It is not rare to find this species in cateniform filaments of 50 or even 70 

 fronds. Nordstedts var. y omata (with aculei on the incisions), found in Brjazi] 

 (Desm. Brås. j>. 221, t. II, f. 16) is, like var. (i supra, longer than broad. The Zygo- 

 spore (f. 15 Nob.) has Diam. s. spin. 45, c. spin. 78 f*. 



