. The essentials of botany. Botany. CABPOPEYtA. irS solve and, the watery portions evaporating, leave a. dusty mass of black spores. The spores germinate by sending out a short filament much as in the wheat-rust (Fig. 95, A and J5), 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 foregoing. Comparing the spores of the Smuts with those of
. The essentials of botany. Botany. CABPOPEYtA. irS solve and, the watery portions evaporating, leave a. dusty mass of black spores. The spores germinate by sending out a short filament much as in the wheat-rust (Fig. 95, A and J5), 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 foregoing. Comparing the spores of the Smuts with those of the preceding orders, we here consider them as sac-spores (ascospores), and the mass of tissues in wliich they are produced, as a degraded spore- fruit. Tlie orderly arrangement of spore-sacs so evident in the Cup-fungi is less marked in the more parasitic Black Fungi; it is scarcely notice- 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 several smutted ears of Indian corn. Mount a little of the black internal mass in water and observe the spores. (J) 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 be readily collected in June or a few days after the "heading" of the grain (wheat, oats, or barley).. Fia. 96. — Ends of three spore - bearing filaments (spore-sacs?) of Indian-corn Smut, showing, a, 6, young spores; c, a spore nearly ripe. Magni- fied 1800 times. Class IV. Basidiomtcetes {the Puff- balls and Toadstools). 363. The'plants of this class are among the largest and finest of the fungi. They are mostly saprophytes whose. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appeara
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