. The essentials of botany. Botany. 236 PHYLUM VII. CARPOMYCETEAE tissues of Plowering Plants. Like the Rusts, they send their parasitic threads through the tissues of their hosts, and afterward produce spores in great abundance which usually burst through the epidermis. There is a still greater structural degra- dation in the plants of the present order than in the Rusts, probably due to their excessive parasitism. Fig. 114.âTeiio- 405. The Darasitic threads of the spore and sponds. *â Smuts are well defined, and consist of thick-walled, cellular, branching filaments, which are generally of v
. The essentials of botany. Botany. 236 PHYLUM VII. CARPOMYCETEAE tissues of Plowering Plants. Like the Rusts, they send their parasitic threads through the tissues of their hosts, and afterward produce spores in great abundance which usually burst through the epidermis. There is a still greater structural degra- dation in the plants of the present order than in the Rusts, probably due to their excessive parasitism. Fig. 114.âTeiio- 405. The Darasitic threads of the spore and sponds. *â Smuts are well defined, and consist of thick-walled, cellular, branching filaments, which are generally of very irregular shape. They grow in the intercellular spaces and cell cavities of their hosts, and some send out suckers (haustoria), which penetrate the adjacent cells much as in the Mildews. The parasite generally begins its growth when the host plant is quite young (meristematic) and grows with it, spreading into its branches as they form, until it reaches the place of spore-formation. In perennial plants the parasite may be perennial, reappearing year after year upon the same stems, or upon the new stems grown from the same roots; in annuals it must obtain a foot-hold in the young plants as they grow in the spring. 406. The life history of the Smuts has been made out for but few species. Three kinds of spores (conidia, teliospores and sporids) have been observed in many species, and their germination has been carefully studied, but the sexual organs (if any exist) have not yet been discovered. 407. The Smut of Indian corn {Ustilago maydis) is very common in autumn. The parasitic filaments are found in various parts of the host, and at last those which reach the young kernels or other succulent parts become semi-gelatinous and form spores internally. There is. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work
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