. Plant studies; an elementary botany. Botany. REPRODUCTIVE ORGANS 119 dry, and are of considerable service in the discharge of spores. In the common ferns a heavy spring-like ring of cells encircles the delicate-walled spore case. When the wall becomes dry and comparatively brittle the spring straightens with considerable force, the delicate wall is suddenly torn, and in the recoil the spores are dis- charged (see Fig. 45). Even in the case of the pollen- spores of seed-plants, a special laver of the wall of the pollen-sac usually develops as a spring-like layer, which assists in opening wide
. Plant studies; an elementary botany. Botany. REPRODUCTIVE ORGANS 119 dry, and are of considerable service in the discharge of spores. In the common ferns a heavy spring-like ring of cells encircles the delicate-walled spore case. When the wall becomes dry and comparatively brittle the spring straightens with considerable force, the delicate wall is suddenly torn, and in the recoil the spores are dis- charged (see Fig. 45). Even in the case of the pollen- spores of seed-plants, a special laver of the wall of the pollen-sac usually develops as a spring-like layer, which assists in opening widely the sac when the wall be- gins to yield along the line of break-. 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 Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
Size: 1115px × 2242px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcou, bookcentury1900, bookdecade1900, booksubjectbotany
