BRITISH DESMIDIEiK. 85 



Tab. XIV. fig. 1 . a. frond with ondochromc ; b. empty frond ; c. transverse 

 view ; d. end view. 



10. E. ansatum (Ehr.) ; segments inflated at the base, and tapering 



upwards to the notched but not dilated extremity ; transverse view 



cruciform. 



Euastntm aiisatum, Ehr. In/us. p. 162. t. 12. f. 6. (1838). 



Euastrum , Bailey, in Amer. Journ. of Science and Arts, v. 41. p. 295. 



t. 1. f. 27. (1841). 

 Euastrum Didelta, Ralfs, Annals of Nat. Hist. v. 14. p. 190 (in part), t. 7. 



f.2. c, d, e,f. (1844) ; Trans, of Bat. Soc. of Edinburgh, v. 2. p. 127. 1. 1 1. 

 Euastrum bitiaJe, Kiitz. Phy. Germ. p. 135 (1845). 



Common. North and South Wales, and Penzance, /. R. Hants, Surrey 

 and Sussex, Mr. Jenner. Kerry, Mr. Andrews, Aberdeenshire and Banff- 

 shire (altitudes 200-3600 feet)'. Dr. Dickie and Mr. Grant. Cheshire and 

 Westmoreland, Mr. Sidebotham. Near Manchester, Mr. WiUiamson. Near 

 Bristol, Mr. Thwaites. Rochdale, Mr. Coates. 



France, Brebisson. Germany, Ehrenberg and K'dtzing. United States, 

 Bailey. 



Frond smaller than that of E. Didelta, twice as long as broad ; the seg- 

 ments mflated at the base and tapering upwards into a neck, which is not 

 dilated at the end ; the terminal notch is linear. The end view has two cir- 

 cular and entire lobes, and the transverse view a single inflation on each side. 

 The empty frond is pmictate. 



I formerly considered this plant as the young state of E. Didelta, and I am 

 not yet fully persuaded that it is distinct ; but as it differs from E. Didelta in 

 every view, and Mr. Jenner, whose opinion I highly value, urges their sepa- 

 ration, I have raised this form to the rank of a species : whether it is right to 

 consider it one, experience must decide. 



Euastrum ansatum is separated from E. circulare by the absence of the five 

 tubercles at the base of the segments in the front view ; in respect of the other 

 species its form is a sufficient distinction. 



Length of frond g-j-g- of an inch ; breadth at base ^-L. ; breadth at end j^-g-. 



Tab. XIV. fig. 2, a. frond with endochrome ; b, e. empty fronds ; d, side 

 ■\-iew ; e. transverse \aew ; f. end view. 



II. E. circulare (Hass.) ; segments three-lobed, mostly with five basal 

 tubercles ; four of them usually disposed semicircularly about the 

 fifth ; end notched, scarcely dilated. 



a. Segments inflated at the base and attenuated upwards. 

 Euastrum circulare, Hass. Brit. Freshwater Algce, p. 383. t. 90. f. 5. (184.5). 

 ^. Segments emarginate at the sides, the basal portion with five 

 tubercles. 

 Euastrum sinuosum, Lenormand, in herb. (1845). 



7. Segments emarginate at the sides ; tubercles smaller, more 



numerous and scattered. 



g2 



