. Fig. ioo.— spores of species of Ustilaginaceae. I, Ustilago ariindinellae; 2, Tillctia decipiens, the secondary spores producing tertiary spores ; 3, Tilletia sonata. All highly mag. (.After Brefeld.) known as 'smuts' and 'bunts.' Teleutospores only are known in this group. In some instances infection takes place in the earliest seed- ling stage of the host-plant, the spores being present in the soil, or adhering to the seed when sown, as in oats. In other instances infet tion occurs in the flower, spores being deposited on the stigma, and a myceliimi is found in the ovary, as i
. Fig. ioo.— spores of species of Ustilaginaceae. I, Ustilago ariindinellae; 2, Tillctia decipiens, the secondary spores producing tertiary spores ; 3, Tilletia sonata. All highly mag. (.After Brefeld.) known as 'smuts' and 'bunts.' Teleutospores only are known in this group. In some instances infection takes place in the earliest seed- ling stage of the host-plant, the spores being present in the soil, or adhering to the seed when sown, as in oats. In other instances infet tion occurs in the flower, spores being deposited on the stigma, and a myceliimi is found in the ovary, as in wheat. In maize, on the other hand, infection can take place during any age, so long as young tissue is present. The teleutospores on germination produce a pro- mvcelium which gives origin to secondary spores; these in turn often germinate and l)ear a third form of spore. In r/s7/7f?;''cUhe spores on germination produce minute secondary spores which increase in number by gemmation or budding,
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Photo credit: © The Bookworm Collection / Alamy / Afripics
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Keywords: ., bookpublishernewyorkmacmillan, booksubjectplantdis, bookyear1910
