~ t x 
O22. Structural and Physiological Botany. 
lil BASSI DIOMY'CETES: 
a. Zremellini. b. Hymenomycetes. c. Gasteromycetes. 
There is still much to learn with regard to the cycle of development. 
of the Basidiomycetes ; and no alternation of generations has yet been 
established in them. The 7veme/lini are distinguished by their jelly- 
like substance, and the two other families by their receptacles. In the 
flymenomycetes are included the commonest and best known ofall Fungi, 
_the mushrooms. The body which is ordinarilycalled the mushroom is, 
as has already been mentioned, only the receptacle, which springs from 
a mycelium growing in the ground, the wood, or elsewhere. A number 
of these Fungi, as Agaricus campestris the common mushroom, A. ce- 
sareus, A. procerus the ‘parasol-mushroom,’ A. prunulus the ‘ plum- 
mushroom,’ A. deliciosus, Boletus edulis, Cantharellus cibarius the 
‘ edible chantarelle,’ &c., are edible ; while others, as Avaricus mus- 
cartus the ‘fly amanita,’ A. emeticus, &c., are poisonous. Merwulins 
lacrymans is the dry-rot so destructive to timber. Among officinal 
species are Loletus laricis and Polyporus fomentarius. Among the 
more common Gasteromycetes are Lycoperdon bovista the ‘ puff-ball,’ 
and Phallus impudicus the ‘stink-horn’ (Figs. 392, 393, pp. 264-5). 
TV... ASCOMMCETES: 
a. Protomycetes. b. Tuberacee. c. Onygenet. d. Pyrenomycetes. 
e. Luscomycetes. 
The spores of the Ascomycetes are formed in ascz by free cell-for- 
maticn. In the Protomycetes the filaments which bear the asci (asco- 
phores) are not united into a receptacle, as in the other families, and 
there is no alternation of generations in their cycle of development. 
This lattec is also wanting in the Tuberaceee (truffles) and the Ony- 
genei; but occurs in the Pyrenomycetes and Discomycetes. The 
Tuberacee form roundish tuberous usually subterraneous bodies, which 
are often surrounded by a copious branched mycelium. Scarcely any-— 
thing is known with regard to their mode of reproduction ; ascospores 
are at present the only kind of spores which have been observed in 
them ; and these are often set free by the rupture of the peridium. 
Their mycelium disappears when the fructification ripens, and the re~ 
~ceptacle then lies naked in the soil (Fig. 394, p. 266) ; while in the Ozy- 
genet it is imbedded in a flocculent mycelium. The asci of the Pyre- 
