. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 303 Son agglutinated Spore-balls (variable) composed of thick-walled spores 10. Tolyposporella. Spore-balls with peripheral spores and central sterile cells 11. Testicularia. Of these genera numbers three to eleven inclusive occur on un- important plants. Among them are: Polygonum, Rynchospora, Psilocary, Cyperus, Carex, Luzula, Juncus, Fimbrystylis, Cissis; various unimportant grasses, members of the Carduaceae, Faba- ceae, Nyctaginacese, Amarantaceae, Cyperacese, Dracenaceae, and Eriocaulacese.
. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 303 Son agglutinated Spore-balls (variable) composed of thick-walled spores 10. Tolyposporella. Spore-balls with peripheral spores and central sterile cells 11. Testicularia. Of these genera numbers three to eleven inclusive occur on un- important plants. Among them are: Polygonum, Rynchospora, Psilocary, Cyperus, Carex, Luzula, Juncus, Fimbrystylis, Cissis; various unimportant grasses, members of the Carduaceae, Faba- ceae, Nyctaginacese, Amarantaceae, Cyperacese, Dracenaceae, and Eriocaulacese. The most important genera are Ustilago and Sphacelotbeca. Ustilago (Persoon) Roussel (p. 302) Sori on various parts of the hosts, at maturity forming dusty spore masses, usually dark colored; spores single, produced irregu- larly in the fertile mycelial threads which early entirely disappear through gelatinization, small to medium in size; germination by means of a septate promycelimn producing only infection-threads or with sporidia formed terminally and laterally near the septa; sporidia in water usually germinate into infection-threads but in nutrient solutions multiply indefinitely, yeast- » fashion. About two hundred species, seventy-two of which are given by Clinton ^ as occurring in America. Besides the species discussed below many others occurring upon grasses or other plants of minor value are omitted. U. avenae (Pers.) ;' "«• "^' ''''• '^^ Sori in spikelets, rarely in leaves, forming a dusty olive-brown spore-mass, about 6-12 mm. Fio. 2i9.—u. aye- long by half as wide, usually rather completely in water. After destroying floral parts, eventually becoming dissi- "* pated; spores lighter colored on one side, subspherical to spherical though often elongate, minutely echinulate, 5-9 n in length, widespread on oats. The fungus was known by the name Ustilago as early as 1552. Please note that these images are extracted from scanned page ima
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
