Fungous diseases of plants . e the parts of the leaf occupied by the fungus (Fig. 95). XXX. COMMON MILDEW OF TREESFhyllactitiia Corylea (Pars.) Ivarst. Palla, E. Ueber die Gattung Phyllactinia. Ber. d. deut. hot. (Jes. 17: 64- 72. , E. S. On Certain Structures in Phyllactinia. Journ. Bot. 37 : 449- 454. pi. 402. 1899. This species of mildew is so distinct from those previously dis-cussed that it is by somemade the type of a sub-family. As previouslystated, no haustoria arepresent, but special seta-like branches penetratethe host. The peritheciumis large and provided withhyalin
Fungous diseases of plants . e the parts of the leaf occupied by the fungus (Fig. 95). XXX. COMMON MILDEW OF TREESFhyllactitiia Corylea (Pars.) Ivarst. Palla, E. Ueber die Gattung Phyllactinia. Ber. d. deut. hot. (Jes. 17: 64- 72. , E. S. On Certain Structures in Phyllactinia. Journ. Bot. 37 : 449- 454. pi. 402. 1899. This species of mildew is so distinct from those previously dis-cussed that it is by somemade the type of a sub-family. As previouslystated, no haustoria arepresent, but special seta-like branches penetratethe host. The peritheciumis large and provided withhyaline, rigid, acicular ap-pendages, each with a swol-len base. There are manyasci, containing 2 or 3spores (Fig. 86, c). The de-velopment of the asci hasbeen discussed (Mg. 85). This species occurs morecommonly uj^on shrubs ortrees, but it is also para-sitic upon a limited num-ber of herbaceous is known to be distributed throughout the northern hemisphere,and is frequently one of the more common of the surface Fig. 95. Yellow Leaf of Maple, withGreen Areas occuiIed by Uncinula 232 FUNGOUS DISEASES OF PLANTS XXXI. HYPOCREACE/E In this family the myceHum is Hght or bright colored, neverdark, as is also the stroma when present. Perithecia are alsocolored and vary from a buff or yellow to brown, red, or purple,never black. They are usually more or less flask-shaped, freeupon the substratum, borne upon a mycelial weft (subiculum),upon a stroma, or imbedded partially or completely in a stroma(well-differentiated perithecial walls are absent in Claviceps, etc.).The perithecium possesses a distinct ostiolum or mouth. Theasci are cylindrical or clavate fusiform. The spores (usually eight)are diverse in form, and they sometimes bud within the ascus. Pa-raphyses may be present. In general, the family is distinguishedfrom other pyrenomycetes only by color and texture. In this large family impoitant pathological forms may be se-lected from three genera,— Neocosmospora, Nec
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