. The essentials of botany. Botany. OABPOPHTTA. 175 solve and, the watery portions evaporating, leave a dusty mass of black spores. The spores germinate hy sending out a short filament much as in the wheat-rust (Fig. 95, A and B), upon which minute sporids are formed. The subsequent history of the sporids is not known. 362. Other Smuts, as Grain-smut or Black Blast (Ustilago segetum) of wheat, oats, and barley, and the Bunt or Stinking- smut (Tilletia tritici) of wheat have a structure and mode of development close- ly resembling the Fio. 96.— Ends of three spore - bearing filament
. The essentials of botany. Botany. OABPOPHTTA. 175 solve and, the watery portions evaporating, leave a dusty mass of black spores. The spores germinate hy sending out a short filament much as in the wheat-rust (Fig. 95, A and B), upon which minute sporids are formed. The subsequent history of the sporids is not known. 362. Other Smuts, as Grain-smut or Black Blast (Ustilago segetum) of wheat, oats, and barley, and the Bunt or Stinking- smut (Tilletia tritici) of wheat have a structure and mode of development close- ly resembling the Fio. 96.— Ends of three spore - bearing filaments (spore-sacs?. Comparing the spores of the Smuts with those of the precediug orders, we here consider them as sac-spores (ascospores), and the mass of tissues in which they are produced, as a degraded spore- fruit. The orderly arrangement of spore-sacs so of indian-oorn Smut, evident in the Cup-fungi is less marked in the Iporesf' "' a' ^sporl more parasitic Black Fungi: it is scarcely notice- 2*?''J?„„'''.P®- Magni- T,i • *i, -D t 1-1 • *i o . -i^ fled 1800 times, able in the Rusts, while in the Smuts it has en- tirely disappeared. As the parasitism increases the structural degra- dation also increases. Practical Studies.—(a) Collect smutted ears of Indian corn. Mount a little of the black internal mass in water and obsei've the spores. (6) Make very thin slices of young fresh specimens and examine for parasitic and spore-bearing filaments. The outer tissues of the distorted kernels are generally best. (c) Make similar studies of the Grain-smut, which may he readily collected in June or a few days after the "heading" of the grain. Here should come a great number of reduced Sac-fungi (including the Yeast-plants, p. 110) and the so-called Imperfect Fungi. Class IV. Basidiomtcetes {tJie Puff-halls and Toadstools). 363. The plants of this class are among the largest and fioest of the fungi. They are mostly saprophytes whose. Please note that these imag
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