86 MORPHOLOGY 



(c) Auiiculariales 



These are the ear fungi, appearing as gelatinous, earlike growths on bark, 

 board fences, etc., a very common form being seen on old stems of elder. When 

 moist, the ear is gelatinous and brightly colored ; when dry, it becomes hard and 

 gray and wrinkled, and externally hairy. This ear is a, complex sporophore aris- 

 ing from a mycelium, its internal surface being lined with a hymenium. A section 

 of the hymenium shows basidia transversely divided into four cells, each cell giv- 

 ing rise to a. slender branch (sterigma) which produces a basidiospore. This 

 basidiura so much resembles that of the Uredinales (the promycelium) that the 

 ear fungi are sometimes grouped with them ; but the complex sporophore is dis- 

 tinctly like that of the fleshy fungi. 



(d) Tremellales 



These fungi also appear as gelatinous growths on decaying wood and tree trunks, 

 these growths being complex and more or less indefinite sporophores from a myce- 

 lium. When moist, they appear usually as thick, wavy, or folded coatings of 

 quivering gelatinous consistency and indefinite form. The wavy ridges are coated 

 with a hymenial layer, and the basidia are peculiar in being divided longitudi- 

 nally into four cells, each cell terminating in a long, slender filament (sterigma) 

 bearing a, basidiospore. 



II. AUTOBASIDIOMYCETES 



These are the true Basidiomycetes, the ba.s)dium being one-celled, 

 and they constitute the large assemblage of forms known as the fleshy 

 fungi. Two great 'subgroups are recognized: (I) Hymenomycetes, in 

 which the hymenium is exposed; and (II) Gasieromycetes, in which the 

 hymenium is inclosed. 



I. Hymenomycetes 



(e) Dacromycetales 



These forms are interesting on account of their evident relationship to the Tre- 

 mellales, which they resemble in their gelatinous sporophores. The one-celled 

 basidium forks into two long sterigmata, and hence produces two basidiospores. 

 It has been discovered that the nuclear fusion in the basidium is followed by two 

 successive divisions, resulting in four nuclei, as in all basidia. In spore forma- 

 tion two nuclei remain in the basidium, or the two nuclei may move in pairs into 

 the sterigmata, one of each pair entering the terminal spore. 



(f) Exobasidiales 



This group of parasites attacks, among other hosts, members of the heath family, 

 as huckleberries, cranberries, etc., the tips of the shoots, buds, flowers, or young ova- 

 ries of the host becoming enlarged and distorted into gall-like growths. These 

 affected parts finally become covered with a. whitish bloom, made by the basidia 



