. A manual of botany. Botany. 70 MANUAL OP BOTANY ^-^y^^- sexual apparatus is formed, but it is doubtful how far actual fusion of the gametes takes place. The gametes may be alike. In this case they are never set free from the gametangia, but the walls of the latter coalesce and fusion takes place inside the structure so formed, a zygospore being the result {fig. 820). These isogamous fungi form the group of the Zygomycetes. In other cases both male and female gametes are found. The female is usually an oosphere, contained either singly or in numbers inside a structure that may be called an oo
. A manual of botany. Botany. 70 MANUAL OP BOTANY ^-^y^^- sexual apparatus is formed, but it is doubtful how far actual fusion of the gametes takes place. The gametes may be alike. In this case they are never set free from the gametangia, but the walls of the latter coalesce and fusion takes place inside the structure so formed, a zygospore being the result {fig. 820). These isogamous fungi form the group of the Zygomycetes. In other cases both male and female gametes are found. The female is usually an oosphere, contained either singly or in numbers inside a structure that may be called an oogonium {fig. 821). In this case the male usually consists of a mass of naked protoplasm, which occurs in a special branch of one of the hyphse, in close proximity to the oogonium. This branch is' known as a polUnodium {fig. 821,aw). In another section the male gametes are differentiated and are set free. They are small rounded cells, clothed with a cell- wall, and known as spermatia. They are produced by abstriction from the apex of a special filament, the sterigma, a number of these being developed in a, special re- ceptacle, the spermogoniuvi. The into contact at their apices, and each female organ, which is known as has cut off from itself a cell. s:yg. ââ rt«â7,v«««,*, / j;⢠r7oo\ âi. â Zygospore resulting from the fusion ⢠arcUcarp {fig. 783), contams of these cells, zyg'. Adult zygospore no differentiated female cell, and after germination, p. Promycelium n i. x, . ^ bearing a sporangium, sp. corresponds to the procarpmm of the Rhodophyoese. This some- times has a trichogyne, as in the latter group. In some forms which bear an archicarp the male cell is not dififerentiated either, but is much like the gamete of the group last mentioned, being produced by a hypha close to the archicarp. The product of fertilisation in the last two cases is known as an ascocarp, and is the sporophyte of the plant. The spores or gonidia of fungi are borne in great numb
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