KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 91 



Wallich. Beng. Desm. p. 280. 



Bengal, »somewhat sparingly». 



In Wallich's memoir the author maintained that this and the preceeding species 

 were but varieties of one and the same plant; again st this view Mr. W. Archek, in 

 two papers (X. H. Soc. Dubl. 5 Apl. 1861, and 5 May 1865) contended for their 

 separation. However the diseovery by Lundell (Desm. Suec. p. 12, t. I, f. 2, 1871) 

 that Mic. rotata had a dissimilar zygospore from that of M. (hnticulata (Ralfs, Br. 

 Desm. t. VII, f. 1 g, 1848), set this vexed question finally at rest. This result onlv shows 

 how apparently closely related forms may Avidely differ in the form of the Zygospore. 



Note. For many years grave doubts existed as to whether the distinguished 

 botanist C. A. Agardh was truly the anthor of the genus Micrasterias (in its modern 

 sense, as the only species described was named by him M. furcata, its diagnosis being 

 very brief, »Micrasterias furcata, radiis pluries furcatis obtusis»). Braun, Alg. Unicell. 

 pp. 65 and 107, refers to this uncertainty, and gives a letter from Dr. J. G. Agardh 

 (1855) to show that the species and genus of 1827 were valid; that the genus was 

 undoubtedly that accepted by Ralfs, but that the species was = M. rotata (Grev.) 

 Ralfs. Braun says, »Probatur igitur Micrasteriam Agardhi cuin Micrasterias genere 

 sensu Ralfsiano convenire et Micrasteriam furcatam Ag. cum M. rotato Ralfs identi- 

 cam esse,» 1. c. p. 108. In the Desm. Bornholm of Dr. Nordstedt (appendix or ab- 

 breviation in French, p. 211) this remark of J. G. Agardh to Braun is referred to. 

 Every one knows that Dr. Agardh, like his illustrious father, was an admirable algo- 

 logist, but in the case of this plant I imagine that the determination was possibly in- 

 correct. Dr. Nordstedt (a veritable Desmid-specialist!) gave me several years ago, a. 

 ligure from C. A. Agardhs original material, thus, »Micrasterias furcata Agdh., se- 

 cundum specimina originalia in herb. J. G. Agardhii, ab O. Nordstedt delineata», I 

 found the ligure was not that of M. rotata, but of M. denticulata! However, in 

 justice to Dr. J. G. Agardh, I must state that it is possible that he in 1855 (like 

 Wallich in 1860, and Rabenhorst in 1868), considered that M. rotata and denticulata 

 were but two forms of the same species, and this may be the true explanation of his 

 letter to Braun. 



11. M. lux, Joshua (Burm. Desm. p. 636, t. 22, f. 12, 1885; M. extendens Turner in litt. 

 1884; M. radiosa var.? Wallich Mscr. No. 82, 1855). 



Long. 180—190, lat. 170—205, lat. isth. 18—22, lat. apic. 44, lat. lob. pol. 18, 

 crass. 25—29 /u. T. VI, f. 6. 



ft Wallichii, n. v. A fronte visa differt forma typica sectionibus lobulorum late- 

 raliurn undulatis, ut in M. radiosa, non rectis et regulariter radiantibus; apicibus 

 lobulorum forcipatis. 



Long. 180, lat, 160, lat. isth. 20, lat, apic. 43, lat. lob. pol. 20//. T. XXII, f. 2. 



Hab. a et (i Bengal, G. C. W.; (i Khasia, G. von L. 



12. M. radians, n. sp. M. sub-circularis, stelliformis, mediocris, subquinque lobata; semi- 

 cellulis sub-5-lobatis, lobis lateralibus radiantibus, bilobulatis; lobulis bifidis; lacinulis 

 rectis apice bicuspidatis vel bidentatis; membrana glabra vel subtilissime punctata; 

 sinu interne lineari, externe modice aperto, angusto-cuneato. 



