. The fungal diseases of the common larch . Larches. THE LARCH CANKER 43 spores from the ascus of this species is between 10 and 15 mm. In a damp chamber such as that described, the spore-ejection may take place very rapidly, and from two small apothecia, measuring 1-25 mm. and 1-5 mm. respec- tively in diameter, 104 spores were found to have been ejected in 2 minutes. In a dry atmosphere the asci cease to shed their spores, a fact which is no doubt correlated with the closing of the apothecia in dry weather. The spores maj' germinate in either of the two following ways : (i) The spores first
. The fungal diseases of the common larch . Larches. THE LARCH CANKER 43 spores from the ascus of this species is between 10 and 15 mm. In a damp chamber such as that described, the spore-ejection may take place very rapidly, and from two small apothecia, measuring 1-25 mm. and 1-5 mm. respec- tively in diameter, 104 spores were found to have been ejected in 2 minutes. In a dry atmosphere the asci cease to shed their spores, a fact which is no doubt correlated with the closing of the apothecia in dry weather. The spores maj' germinate in either of the two following ways : (i) The spores first divide by one, or less commonly. Fig. " 20.—Spores and germination : a, spore, showing nucleus and vacuoles ; B, germinating at both ends ; c, two germ tubes at one end ; D, segmentation ; e, r, G, methods of germination. more septa which are put in at right angles to the long axis of the spore (fig. 20, D, e). The first of these may be completed twenty hours after the ejection of the spore. When the spore becomes divided into three segments (fig. 20, F) these are usually unequal, one being nearly half the size of the whole spore ; a third septum may then be formed in the larger cell. The germ tubes may arise in many different ways. Most commonly one grows out from each end of the spore, or one of them may originate near the middle septum, but cases in which three or four germ tubes arise from a single spore are not infrequent, (ii) The spore may give rise to germ tubes without first becoming. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hiley, W. E. (Wilfrid Edward). Oxford : Clarendon Press
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Keywords: ., bookcentury1900, bookdecade1910, bookpublisheroxfor, bookyear1919
