. Black rot, leaf spot and canker of pomaceous fruits. Black rot; Leaf spots; Canker (Plant disease); Apples. TYPES OF ASCOSPOUES SALOSPORA CYDONIAE from 21 to 32 ix b> 130 to 180 il. The tip of the ascus is thickened, but a complete canal from the inner wall to the outside has not been observed; only a suggestion of such a canal has been seen even after the peri- thecia had been kept in a moist chamber for several hours. Varia- tions of asci from different hosts are shown in figure 20. The ascospores are ellipsoidal, or often inequilateral (Fig. 21); they measure from to ix by 23
. Black rot, leaf spot and canker of pomaceous fruits. Black rot; Leaf spots; Canker (Plant disease); Apples. TYPES OF ASCOSPOUES SALOSPORA CYDONIAE from 21 to 32 ix b> 130 to 180 il. The tip of the ascus is thickened, but a complete canal from the inner wall to the outside has not been observed; only a suggestion of such a canal has been seen even after the peri- thecia had been kept in a moist chamber for several hours. Varia- tions of asci from different hosts are shown in figure 20. The ascospores are ellipsoidal, or often inequilateral (Fig. 21); they measure from to ix by to yu, averaging by 28//. They are hyaline to greenish yellow. Under ordinary conditions the spores show a very thin gelatinous sheath, but after they have been in a satu- rated atmosphere for a few hours the sheath becomes very broad and evi- dent. The arrangement of the spores A. Typical mature ascospores as found in nature; in the aSCUS IS more Or leSS blSenate. B. ascospores, showing stages in the development of ««~~~'U r-^c o*-^ ^ic-f-i-,-, f n-n^ o*-c the gelatinous sheath; c. old ascospores, showing ->-ne parapnyses are distinct ana are peculiar contents occasionally branched near the tip. Not infrequently the apex shows a tendency to be clavate. The number of spores in each ascus is typically eight, but exceptions have been found in the fungus on apple twigs. The variation ranges from two to eight spores within an ascus, all intervening numbers having been observed. Four-spored asci are not uncommon (Fig. 20). The contents of ascospores are either densely granular, or vacuolate and oily. Two guttules are occasionally found. pycnidia. The morphology of the pycnidial form of this fungus is variable (Fig. 22). The pycnidia are situated in the cortical tissues and are usually scattered and distinct, although on the same organ of the host they may be single, confluent, or united into a stroma. The number of pycnidia per unit of area is usually less on
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectblackro, bookyear1916
