52 H. MARSHALL WARD. 



mycetes, on the other hand, we have the sexual process and typical 

 saprophytic habits together, while in the Saprolegnice the case seems 

 doubtful. 



Looking still more closely into the matter, it appears as if the 

 absence or presence of sexual organs (or their rudiments) rises or falls 

 with the nature of the parasitism or saprophytism displayed. In the 

 jSajirolegnice, for instance, the Fungi may probably be looked upon as 

 very highly nourished by the decomposing proteids of animals. 1 Their 

 sexual organs seem to be present in most cases, but functionless. 



In the Zygomycetes, which are essentially saprophytes on decaying 

 vegetable matter, &c, or parasitic on one another — and may probably 

 be regarded as not so highly nourished — we find the sexual organs 

 functionally perfect, though very simple in character. 



In the UstilaginecB we meet with parasitism of a peculiarly high 

 order, so to speak. The fungus not only robs its host, but has in most 

 cases curiously adapted its life to the habits of the latter, using it 

 rather as a slave than as a victim to be destroyed forthwith. 



The same is true for the highly organised Uredinece (sEcidiomycetes)) 

 and we here meet with the highest adaptation of all, heteroecism. But 

 in these two groups the search for sexual organs has proved utterly 

 futile (if we except the so-called " copulation " of the " sporidia " in 

 Ustilaginece, which cannot be regarded as an essential process, or as 

 sexual in the above meaning). 



Again, if we proceed upwards from the Erysiphece, which are epi- 

 phytes—adapting themselves to parasitic habits of that special kind 

 which leads to life in the interior of temporary organs like leaves — 

 through the Ascomycetes, we find, speaking generally, more and more 

 tendency towards close and specially adapted parasitism, ending in the 

 Lichens, the parasitic Pezizas, forms like the Pleospoms, &c, and 

 especially Claviceps. 



Now it is at least remarkable that no trace of sexual organs has yet 

 been found in the higher Lichens — i.e. in those forms in which the 

 fungus makes a particularly well-regulated use of its slave-like host, 

 which is an Alga containing chlorophyll. Krabbe 2 considers that in 

 Sphyridium the fructification arises independently of any process of 

 fertilisation, and my own observations on Strigula complanata 8 lead to 

 the same conclusion. It will be noted that in the beautiful case de- 



1 If not, indeed, hj living flesh. Cf. Prof. Huxley, ' Quart. Journ. Mic. So.,' 1882. 



a 'Bot. Zeitg.,' February, 1882, No. 5. 



3 'Linn. Trans., ser. 2, Bot.,' vol ii, 1884. 



