INTRODUCTION TO CRYPTOGAMIC BOTANY. 317 



South Carolina on Ephedra. While Ra'sfella affects under 

 one form Poniaceous plants in the northern hemisphere, it 

 reappears at the Cape, attacking the same natural order, 

 and at Ceylon several species occur on very different plants. 

 The curious genus SartveUia (Fig. 72, a) has been found only 

 in Surinam. The great requisite for their growth appears to 

 me an atmosphere charged with moisture, while the ground 

 itself is dry; in other words, a damp air without much rain. 

 A constantly dripping country is certainly not favourable to 

 their growth, nor, indeed, to Fungi in general. 



841. The species of the second group are no less widely 

 diffused. Little, however, is known of tropical species, but 

 Sporodesmium Lepraria accompanies the white spruce as 

 far as its branches are drifted by the waves. Such obscure 

 objects seldom engage the attention of travellers ; but New 

 Zealand, at least, is not without them. Dr. Hooker, who neg- 

 lected nothing which could possibly interest the naturalist, did 

 not gather any species among the Himalayas. On the con- 

 trary, they abound in North America, and a species was 

 gathered by Darwin, at the Falkland Islands, on wood, which 

 had, however, been evidently carried there from a distance. 

 As regards the third division, wherever Sphceriw occur, they 

 are their constant attendants, but they are also found apart 

 from that genus. I have, on drifted wood from Wellington 

 Channel, a little species of PJioma, identical with one which 

 occurs in England on exposed wooden palings, with indications 

 of another species, both, I think, the growth of the sj^ot where 

 they were found, without a trace of true ascigerous Fungi. In 

 Auckland Island and New Zealand a few species occur, and if 

 little is known of tropical species it may be because such ob- 

 jects are little attended to. The dry and decaying leaves in 

 such countries are not, however, altogether without their 

 species. I have, for instance, a Pestalozzia from Cuddapah, 

 and an Excipula from Secunderabad. 



342. As regards iitility little can be said of these Fungi, 

 while, on the contrary, they are the bane of Agriculturists, and 

 sometimes destroy all his hope. The Sorghuon of hot coun- 

 tries, and the maize of warm districts, are not less surely their 



