. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 218 FUNGOUS DISEASES OF PLANTS insufficient data. The evidence is more conclusive with reference to the mil- dew on species of Hordeum and also the one on the Brome grasses. Salmon ... has investigated both of these. The mildew on barley {Hordeum vul- gare) will infect this species and also Hordeum distichum, H. decipiens, H. Hexastichum, H. intermedium, and H. Zeocriton, but will not pass over to Hordeum jubatum, H. bulbosum, H. murinum, H. secalinum, H. sylvaticum. In some of the
. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 218 FUNGOUS DISEASES OF PLANTS insufficient data. The evidence is more conclusive with reference to the mil- dew on species of Hordeum and also the one on the Brome grasses. Salmon ... has investigated both of these. The mildew on barley {Hordeum vul- gare) will infect this species and also Hordeum distichum, H. decipiens, H. Hexastichum, H. intermedium, and H. Zeocriton, but will not pass over to Hordeum jubatum, H. bulbosum, H. murinum, H. secalinum, H. sylvaticum. In some of these cases, however, the number of trials is very small. Morphological. With only one or two exceptions (notably Sphcerotheca Mors-nvce)- the superficial mycelium of these plants consists of colorless hyphas, considerably septate, each cell being ordinarily uninu- cleate. In all species except two, so far as is known, the haustoria penetrate the epi- dermal cells in the form of short, swollen branches. However, in one common mildew of shrubs and trees (Phyllactinia Corylea) hy- phal branches grow through the stomata and into the. Fig. 84. Habit of a Powdery Mildew intercellular spaces. These branches may in turn develop haustoria, which enter the cells in contact with this intercellular hypha. As a rule conidial production in all forms begins whenever a con- siderable mycelium has been developed. These conidia consist, quite generally, of a single chain of cylindrical or more or less barrel-shaped unicellular portions produced in basipetal order on short, erect conidiophores, developed directly from a hyphal cell. The conidia are capable of immediate germination, and since they are produced in quantity, they frequently give the mealy or powdery appearance to the parts affected. They serve for the rapid propagation of these fungi. The conidial stage was for a long time unconnected with the perithecium form and was then known under the form-generic name Oidium. The minute char- act
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Keywords: ., bookauthorduggarbe, bookcentury1900, bookdecade1900, bookyear1909
