202 



INTRODUCTION TO CRYPTOGAMIC BOTANY. 



unknown in the south of England. It descends, however, on 

 the coast of North America, as far as lat 44° 35'. There are 

 several beautiful forms which occur at the Cape, and in 

 other warm seas, which are not found elsewhere ; some of them 

 exhibiting far less conspicuously the cellular reticulation, 

 which is so striking in most of our northern species. Amongst 

 these Is Claudea, the most elegant of aU Algje, of which 

 specimens occur of extreme beauty, and a fine species has lately 

 been added to this Australian genus. One species of Dasya is 

 very remarkable, as calling to mind the genus Bulbochcete; 

 and other striking cases of analogy might easDy be pointed out. 



Fig. 50. 

 Leveillea Schimperi, Den. 

 a. Tip of shoot to show the imbrication of the leaflets, the radicles, 

 and circinate tip. 



h. Single leaflet, with an eroded tip and tubseform radicle.* 



c. Tip of entire leaflet. 



d. Stichidium, the tip of which is circinate, and bears imbricated leaf- 

 lets, all magnified. From specimens communicated by M. Lenormand. 



180. The genus-dmawsia, which has two extra-tropical species, 

 assumes, together with Leveillea and Polyzonia, the forms of 

 Jungermannios; and what, is verycurious,inievei.Me(Xthe frond 

 is circinate, throwing down roots from the midrib. They are 



* Such radicles occur in Polysiphonia. Voyage au Pol Sud, tab. 5, 

 fig. 2. Niig. Zeitschrift, 1847, tab. 8, fig. 18, 19. 



