CHLO'ROPHYTEIE (Neu-Lat. none. pl., from Gk. xi.troGr, chloros, greenish-yellow + oixoc, phykoR, seaweed). One of four great groups of algae, and commonly called the green alga'.
It comprises a large and diverse assemblage of orders and families, partly described in the arti cle Abox (q.v.). The color of the cells is gen erally clear green, due to chlorophyll which is not masked by the presence of other pigments, as in the red, brown, and blue-green alga;. The types of Chlorophyce:e range from one-celled forms to those as conspicuous as the sea-lettuce (Ulva) and stoneworts (Charales). The lower groups generally live in water. where they form sediment in the bottom of ponds and ditches, or slimy coatings on the surfaces of water plants or other (Meets. Certain groups are free-swim ming. the veils being provided with cilia. )lany of the simpler forms live in the air, on bark of trees, on stonework, and in other moist and shaded situations. The green growth. pleurococcus, on the north side of trees. is at familiar example.
Among the unicellular forms time desmids are the most conspicuous and beautiful, comprising an immense number of species. Above the uni cellular green algte are found filamentous types, sometimes called confervas, and also membra nous growths especially well illustrated in the sca-lettuces. Some of the filamentous forms
are slimy, and appear as frothy scums on the surface of the water (`pond-scums'). Other kinds, as the genus Vaucherui, form coarse, rough mats at the bottom of ponds and ditches, or on moist earth. The water-net (I/yds-odic/you ) sometimes grows so luxuriantly as almost to fill the water. The highest groups in complexity of body are the stoneworts and certain marine forms, e.g. Canlegal. which are differentiated into stems, leaves, and rootlike organs of at taehment. The resting stages of some Chloro !thyme are very conspicuous. The color of 'red snow' is due to the presence of the resting spores of one of the Volvocales.
Generally speaking, the algal flora of a pond or ditch depends largely on the season of the year, the chemical nature of the water, and the illumination, but also to a great extent upon biological factors involved in the special adaptation of species to one another and their environment.
There are many special monographs covering various orders in this large group, For general treatment, consult Engler and Prantl, Die not r lichen Plhz nzenf am il ien (Berlin, 1899 et seq.).
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