. Elementary botany. Botany. COXTIXUED: CLASSlFICATIOX. '59 ponds. Here in. dry weather il i:^ often foun<! closeh' adhering to the drv rock surfare, and giving it a red(h'sh rolor as if the rock were painted. 'I his is especially the case in the shallow basins furnied over the uneven :^urface of the rock near the water's edge. These places during hcavv rains or in high water are pro^â ided with suflicient water to fill the basins. During such times the red snow plant grows and muUiplies, lo^es its rerl color and. Fig. 162, Sphserella lacustris () Wittrock. A, mature free-swimn
. Elementary botany. Botany. COXTIXUED: CLASSlFICATIOX. '59 ponds. Here in. dry weather il i:^ often foun<! closeh' adhering to the drv rock surfare, and giving it a red(h'sh rolor as if the rock were painted. 'I his is especially the case in the shallow basins furnied over the uneven :^urface of the rock near the water's edge. These places during hcavv rains or in high water are pro^â ided with suflicient water to fill the basins. During such times the red snow plant grows and muUiplies, lo^es its rerl color and. Fig. 162, Sphserella lacustris () Wittrock. A, mature free-swimniing indi\-idual â with central' red spot. B, division of mother individual to form two. C, divi- sion of a red one to f'pical resting cell, red. F, same beginning to divide. G, one of four daughter zoospores after swimming around for a time losing its red color and becoming green. (After Hazen.) becomes green, and, being motile, is free s^^dmming. It is a single-celled plant, oval in form, surrounded by a gelatinous sheath and "with two cilia or flagella at the smaller end, by the vibration of which it moves (fig. 162). The single cell multiplies by dividing into two cells, ^\'hen the water dries out of the basin, the motile plant comes to rest, and many of the cells assume the red color. To obtain the plant for study, scrape some of the red cov- ering from these rock basins and place it in fresh spring water, and in a da^ or so the swarmers are likely to be found. Under certain conditions small microzoids are formed. 336. Chlamydomonas is a very interesting genus of motile one-celled green alga;, because the species are closely related to the Flagellates among the lower animals. The plant is oval, with a single chloroplast and sur- rounded by a gelatinous envelope throvgh which the two cilia or liagella extend. One-celled organisms of this kind are sometimes calle'H vwnads, , a one-celled being. This one has a gelatinous cloak and is, therefore, a cloaked moiiad (C
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