. The classification of flowering plants. Plants. members may occur as in Rhynchospora and Eriophorum (fig. I). In others, as in the large genera Gyperus (figs. 117, C, D) and Carex, the flowers are naked. Two whorls of stamens occur in a few genera or species, but generally a reduction has taken place, the inner whorl being completely absent, or, as in Hemicarpha (fig. 115, C) and Hoppia, only one stamen is present. Three carpels may be present or, as often happens, the number is reduced to two; in Garex (figs. 117, Q, S, 118) both forms occur. The number is indicated by the two or three stig
. The classification of flowering plants. Plants. members may occur as in Rhynchospora and Eriophorum (fig. I). In others, as in the large genera Gyperus (figs. 117, C, D) and Carex, the flowers are naked. Two whorls of stamens occur in a few genera or species, but generally a reduction has taken place, the inner whorl being completely absent, or, as in Hemicarpha (fig. 115, C) and Hoppia, only one stamen is present. Three carpels may be present or, as often happens, the number is reduced to two; in Garex (figs. 117, Q, S, 118) both forms occur. The number is indicated by the two or three stigmas which the style bears. The base of the style is often thickened, forming a beak-like crown to the fruit. The flowers are wind-pollina- ted, self-pollination being often rendered impossible by separation of the sexes. The fruit is biconvex or three- sided according as it originates from two or three carpels; or some- The pericarp is leathery or some- times thick and corky or hard, sometimes stone-like (Scleria). The seed has a thin testa. There are 65—70 genera, containing about 3,000 species and distributed throughout the earth chiefly as marsh-plants. In the Arctic area they form about ten per cent, of the flora. They will flourish in soils rich in humus which are too acid for grasses. There is some difference of opinion as to the subdivision of the order into large groups, but the following tribes are generally recognised. Tribe 1. Scirpeae. Spikelets simj^le, many-flowered, flowers hermaphro- dite, bracteoles absent. Bracts in two rows. Sub-tribe Cyperinae. Bracts spirally arranged in several rows. Sub-tribe Scirpinae. Sub-tribe Cyperinae includes the large genus Cyperus (tig. 117, A—D), with about 400 sjjecies distributed through the tropical and sub- tropical parts of both worlds, becoming rapidly fewer in the temperate zones. It is represented in Britain by two very rare species in the south of England. Cyperios Papyrus is the Egyptian Papyrus. Fig. 118. Diagrams
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectplants, bookyear1904
