8 



FIRST GROUP. 



the procarp is a simple cell, and a small protuberance from it forms the trichogyne. 

 The spermatium coalesces with the procarp, whereupon the carpogenous cell, that is 

 the larger part of the procarp-cell, divides into eight cells which become spores, carpo- 

 yporesfjust as the oosphere of Oedogonium divides into a number of (motile) spores; 

 the only difference is that the oospore first passes through a period of rest ; but 

 bospores too may dispense with this condition, as we learn from Fucus. 



In many other Florideae also the procarp is unicellular, and the elongated neck- 

 like upper part serves as the trichogyne, the lower somewhat dilated part as the 

 carpogenous cell, the carpogone. This is the case with the Nemalieae (Fig. 5). 

 But in them the carpogenous cell produces after fertilisation a number of branches, 

 which break up into single cells, each of which is a carpospore. The spore-producing 

 fructifications formed by the sprouting of the carpogone are called sporocarps. The 

 sporocarp is often completed by the addition of an investment formed by branches 

 which spring from cells adjoining the carpogone; these closely invest the carpogone and 

 its products. A similar envelope occurs in some zygospores and oospores, as in Mor- 

 tierella among the Zygomycetes, and in the oospores of Colcochaete and Chara among 



J) 



FIG. 5. formation of procarp and carpospores in two Florideae. C Nemalien, D Lejolisia, w procarp, 

 unicellular with a long trichogyne in Nemalion, pluricellular with a short trichogyne in Lejolisia, 

 m spermatia, cs carpospores, h envelope of the sporocarp. 



the Chlorophyceae (Fig. 3). In other Florideae (Fig. 5 D] the procarp is pluricellular 

 before fertilisation ; examples of this will be given in discussing the Florideae. 



b. FORMATION OF ARCHICARPS IN THE ASCOMYCETES. Whilst the fertilisation 

 of procarps in the simple forms of the Florideae has some analogy with the formation 

 of oospores by the union of planogametes, the formation of archicarps in the simpler 

 forms of the Ascomycetes is directly related to the formation of the oospores of the 

 Peronosporeae, which results from the union of non-motile gametes. But here a true 

 operation of sexual organs, that is an actual fertilisation, has in no case been proved, 

 and indeed is not probable. The sporocarps of the Ascomycetes are often bodies of 

 considerable size, the most essential elements of which are one or more tube-like 

 cells, placed singly or in groups, and named asci, in which the spores are formed. 



One of the simplest modes of the formation of sporocarps is seen in Podosphaera 

 (Fig. 6 E). Two branches arise from the mycelium, one of which is swollen into 

 the shape of a barrel and forms the archicarp ; the other, which is a thinner and 

 antheridial branch, becomes closely applied to the archicarp, and a small antheridial 



