Cladium and Rhynchospora (Beak-rush) differs especially in the few-flowered, compound spikelets which are collected into small bunches; the latter has received its name from the fact that the lowermost portion of the style remains attached to the fruit as a beak.
2. Spikelets compressed, the bracts arranged only in two rows; the other characters as in the first-mentioned. Cyperus (spikelets many-flowered); Schœnus (Bog-rush); spikelets few-flowered; S. nigricans has an open sheath.
Fig. 285.—Carex: A diagram of a male flower; B of a female flower with 3 stigmas; C of a female flower with 2 stigmas; D diagrammatic figure of a female flower; E similar one of the androgynous (false) spikelet of Elyna. The ♂ is here represented placed laterally; it is terminal, according to Pax.
Fig. 286.—A Flower of Scirpus lacustris. B Seed of Carex in longitudinal section.
B. Cariceæ. Unisexual Flowers.
In the ♂-flowers there is no trace of a carpel, and in the ♀ no trace of a stamen. Floral-leaves in many rows. In some (Scleria, certain Carex-species), ♂-and ♀-flowers are borne in the same spikelet, the latter at the base or the reverse; in the majority each spikelet is unisexual.
Carex (Fig. [285]) has naked, most frequently monœcious flowers. The ♂-spikes, which are generally placed at the summit of the whole compound inflorescence, are not compound; in the axil of each floral-leaf (bract) a flower is borne, consisting only of a short axis with three stamens (Fig. [285] A). The ♀-spikes are compound; in the axil of each floral-leaf is borne a very small branch (Fig. [285] D, a) which bears only one leaf, namely, a 2-keeled fore-leaf (utriculus, utr. in the figures) which is turned posteriorly (as the fore-leaves of the other Monocotyledons), and being obliquely sheath-like, envelopes the branch (in the same manner as the sheath of the vegetative leaves), and forms a pitcher-like body. In the axil of this leaf the ♀-flower is situated as a branch of the 3rd order, bearing only the 2–3 carpels, which are united into one gynœceum. The style protrudes through the mouth of the utriculus. The axis of the 2nd order (a in Fig. [285] D) may sometimes elongate as a bristle-like projection (normally in Uncinia, in which it ends as a hook, hence the name); this projection is in most cases barren, but it sometimes bears 1–several bracts which support male-flowers; this is normal in Elyna (or Kobresia) and Schœnoxiphium; the axis (a in 285 E) bears at its base a female-flower supported by the utriculus, and above it a male-flower supported by its bract.
Pollination by means of the wind. Protogynous. Sometimes self-pollinated. The order embraces nearly 3,000 species, found all over the world. Carex and Scirpus are most numerous in cold and temperate climates, and become less numerous towards the equator. The reverse is the case with Cyperus and other tropical genera. They generally confine themselves to sour, swampy districts; some, on the other hand, are characteristic of sand-dunes, such as Sand-star (Carex arenaria). There are about 70 native species of Carex.