88 BRITISH DESMIDIE^. 



is dilated ; the neck is short, and abovit one-third as broad as the base ; the 

 granulated dilatations of the terminal lobe are inclined upwards, hence the end 

 is broadly emarginate. The transverse view is oblong, with three lobes on each 

 side and one at each end. The end view shows that the terminal lobe is cru- 

 ciform. 



Euastrum gemmattim is a small but elegant species, the base being quadri- 

 lateral, horizontal, and nearly three times as broad as long. It may be known 

 from all in this section, except E. pectinahim, by the absence of a linear ter- 

 minal notch, and from that species it may be distinguished by the smallness 

 of the end lobe and the outward direction of its angles, and by the minute 

 granulation of the projecting parts. 



M. De Brcbisson has kindly furnished me with drawings of Euastrum gem- 

 matum, BreT)., and E. papulosum, Kiitz., the latter of which he reduces to a 

 variety of the former in a MS. list of the species of this genus ; but I must 

 confess that I know not how to make even this distinction between them. 



Length of frond ^^ of an inch ; breadth at base -^\j ; breadth at end -yttq ' 

 breadth of neck yxgr- 



Tab. XIV. fig. 4. a. frond with endochrome ; b. empty frond ; c. side view ; 

 d. end view ; e. transverse view. 



*** Frond without a distinct terminal lobe, and frequently having a 

 process or an acute angle at the corners of the terminal portion. 



14. E. rostratum (Ralfs) ; frond oblong; ends protuberant, emargi- 

 nate and angular, with a horizontal spine on each side. 



Euastrum rostrattim, Ralfs, Annals of Nat. Hist. v. 14. p. 192. t. 7. f. 5. 

 (1844) ; Trans, of Bot. Soc. of Edinburgh, v. 2. p. 129. t. 11. Hass. 

 Brit. Alg. p. 383. 



Dolgelley and Penzance, J. R. Sussex, Mr. Jenner. Near Aberdeen, Dr. 

 Dickie and Mr. P. Grant. Moss Hagg between Tomantaul and Lochavon 

 (alt. 3000 feet), Banffshire, Mr. P. Grant. Near Ambleside, Mr. Sidebotham. 



New York, Bailey. 



Frond very minute, about twice as long as broad ; segments obscurely 

 three-lobed, or rather ha^dng a broad basal portion, which is emarginate at each 

 side and connects itself by a broad short neck vdth the terminal lobe. This 

 terminal portion has on each side a horizontal, subacute, beak -like process, and 

 is prominent, emarginate and angular. 



Euastrum rostratum, like the species in the preceding section, is contracted 

 (though less decidedly) into a neck, and also has emarginate sides ; but it 

 differs from them in its much smaller size, and especially in the horizontal 

 processes of its end lobe. The angular and less prominent ends distinguish it 

 from E. elegans. 



A single sporangium which I gathered at Dolgelley was spinous, like that of 

 E, elegans, but larger. 



Length of frond from ^ig to g-i^ of an inch ; breadth from yoVo^ ^^ tiT- 



Tab. XIY. fig. fi. n, h. fronds with endochrome. 



