. A textbook of botany for colleges and universities ... Botany. ROOTS AND RHIZOIDS 519 and salts through the latter; indeed, the rise of colored liquids has been witnessed in the rhizoids of Polytrichum. When the rhizoids of Catharinea are severed in the soil, the leaves wither precisely as they do in seed plants when the roots are cut. Water drops appearing on cut stem surfaces of Mnium have been supposed to indicate conduction and hence rhizoid absorp- tion. In Polytrichum and in Catharinea the rhizoids are intertwined like the strands of a rope, so that doubtless water can ascend be- tween
. A textbook of botany for colleges and universities ... Botany. ROOTS AND RHIZOIDS 519 and salts through the latter; indeed, the rise of colored liquids has been witnessed in the rhizoids of Polytrichum. When the rhizoids of Catharinea are severed in the soil, the leaves wither precisely as they do in seed plants when the roots are cut. Water drops appearing on cut stem surfaces of Mnium have been supposed to indicate conduction and hence rhizoid absorp- tion. In Polytrichum and in Catharinea the rhizoids are intertwined like the strands of a rope, so that doubtless water can ascend be- tween them by capillar- ity as well as within them. In mat and cushion mosses it is prob- able that leaf absorp- tion, facilitated by the ready capillarity made possible by close con- tact between adjoining shoots, is much more im- portant than is rhizoid absorption (p. 611). Rhizoids of algae and of lichens. — Algae. — Many small algae are entirely unattached, and move actively {Volvox) or drift passively (Pleu- rococcus). Other forms are attached by the muci- lage they exude. Some filamentous algae (as Ulothrix and Oedogonium) are anchored by the basal cell, which may differ from the other cells in shape and color; such forms often are epiphytic on other water plants. Rootlike rhizoids occur in Vaucheria, Botrydium, and Chara. Large marine algae are attached to rocks by much-branched rhizoids (or. Fig. 751. ^ a marine alga {Nereocystis), showing a rhizoid complex or system of haptera, which serves as a holdfast organ, the plant firmly to a rocky sub- stratum below sea level; note the stalk or stipe, whose bladder-like expansion floats the leaflike organs at the water surface. — From Coulter (Part I).. 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; Barnes, Charles R
Size: 1261px × 1982px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
