. Textbook of botany. Botany. 62 TEXTBOOK OF BOTANY finally breaks the epidermis of the leaf. Each cell of the basal layer, like each of the other cells of the fungus up to this time, contains a single nucleus. These basal cells become joined in twos by a dis- solving of part of the walls between each pair of adjoining cells (Fig. 27, D, a) ; the two cells of each pair have now become a single cell of ir-. FiG. 27. — A, a section through a portion of an infected barberry leaf bearing spring spores on the lower surface and spermatia on the upper sur- face. B, a section through a cluster cup, sh
. Textbook of botany. Botany. 62 TEXTBOOK OF BOTANY finally breaks the epidermis of the leaf. Each cell of the basal layer, like each of the other cells of the fungus up to this time, contains a single nucleus. These basal cells become joined in twos by a dis- solving of part of the walls between each pair of adjoining cells (Fig. 27, D, a) ; the two cells of each pair have now become a single cell of ir-. FiG. 27. — A, a section through a portion of an infected barberry leaf bearing spring spores on the lower surface and spermatia on the upper sur- face. B, a section through a cluster cup, showing the spring spores. C, a section through a cavity in which spermatia are being formed. D, the formation of spring spores: j, the union of two gametes in the basal layer of the cluster cup; 6, the two nuclei of the zygote have dividfed; c, the zygote has cut off a two-nucleate cell; d, the zygote has formed a chain of spring spores (e) alternating with small cells (/) which will soon disappear. D after Christman. regular shape, containing two nuclei. The two nuclei of each such irregular cell now divide, one of each pair of daughter nuclei passes to the upper end of the cell, and this end is cut off as a small two- nucleate cell (Fig. 27, D, b and c). Then the two nuclei left in the large lower cell divide again, and another small two-nucleate cell is produced just below the first one. The process of division is repeated again and again, so that a long chain of two-nucleate spring spores is formed (Fig. 27, D, d)} From ' Really each cell of the chain in turn divides into two cells, of which one (the upper) becomes a spore; the lower one remains small and very soon breaks down. 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 Allen, Charles E. (Charles Elmer), b. 1872; Gilbert, Edward Martinius, joint au
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1917
