Some of the numerous Juncus-species (e.g. J. effusus, glaucus, conglomeratus, etc.), have false, lateral inflorescences, the axis of the inflorescence being pushed to one side by its subtending leaf, which apparently forms a direct continuation of the stem, and resembles it both in external and internal structure. The foliage-leaves of this genus were formerly described as “unfertile stems,” because they are cylindrical, erect, and resemble stems, and consequently the stem was said to be “leafless”: J. effusus, glaucus, conglomeratus. Stellate parenchynatous cells are found in the pith of these stems and in the leaves. Other species have distinct terminal inflorescences and grooved leaves; J. bufonius (Toad-rush), compressus, and others. The inflorescences most often present the peculiarity of having the lateral axes protruding above the main axis. Their composition is as follows:—The flowers have either no bracteoles, and the inflorescences are then capitulate; or they have 1–several bracteoles. Each branch has then, first, a 2-keeled fore-leaf placed posteriorly (“basal-leaf”), and succeeding this are generally several leaves borne alternately and in the same plane as the basal-leaf, the two uppermost (the “spathe-leaves”) being always barren; those which lie between the basal-leaves and the spathe-leaves are termed “intermediate-leaves.” If only branches occur in the axils of the basal-leaves, then the succeeding branches are always borne on the posterior side of the axis, and form a fan[27]; if the basal-leaf is barren, and if there is only one fertile intermediate-leaf, then the lateral axes are always on the upper side, and a sickle[27]-like inflorescence occurs; if there are 2 fertile intermediate-leaves, then a dichasium is formed, and in the case of there being several, then a raceme, or spike.
Juncaceæ are, by several authors, classed among the Liliifloræ, but there are so many morphological and partly anatomical features agreeing with the two following orders, that they may, no doubt, most properly be regarded as the starting point of these, especially of the Cyperaceæ, which they resemble in the type of flowers, the inflorescence, the type of mechanical system, and the stomata.
Pollination by means of the wind. Cross-pollination is often established by protogyny. J. bufonius has partly triandrous and cleistogamic, partly hexandrous, open flowers.—Distribution. The 200 species are spread over the entire globe, but especially in cold and temperate countries; they are seldom found in the Tropics.—Uses. Very slight; plaiting, for instance.
Order 2. Cyperaceæ. The majority are perennial (seldom annual) herbs living in damp situations, with a sympodial rhizome and grass-like appearance. The stems are seldom hollow, or have swollen nodes, but generally triangular, with the upper internode just below the inflorescence generally very long. The leaves are often arranged in 3 rows, the leaf-sheath is closed (very seldom split), and the ligule is absent or insignificant. The flowers are arranged in spikes (spikelets) which may be united into other forms of inflorescences (chiefly spikes or racemes). The flowers are supported by a bract, but have no bracteoles. In some genera the perianth is distinctly represented by six bristles corresponding to six leaves (Figs. [284] A, [286] A); in others it is represented by an indefinite number of hairs (Fig. [284] B), and very frequently it is altogether wanting. The inner whorl of stamens is absent, and the flower has therefore 3 stamens (rarely more or less than 3), the anthers are attached by their bases to the filament (innate) and are not bifid (Figs. [286]). Gynœceum simple, formed of 3 or 2 carpels; 1 style, which is divided at the extremity, as in the Juncaceæ, into 3 or 2 arms; the single loculus of the ovary contains one basal, erect, anatropous ovule; the stigmas are not feather-like. Fruit a nut, whose seed is generally not united with the pericarp. The embryo is small, and lies at the base of the seed in the central line, surrounded on the inner side by the endosperm (Fig. [286] B). On germination the cotyledon does not remain in the seed.
Fig. 284.—Diagram of structure of: A Scirpus silvaticus; B Eriophorum angustifolium.
A regular perianth, with 6 scale-like perianth-leaves in 2 whorls, is found in Oreobolus. In Scirpus littoralis the perianth-leaves are spreading at the apex, and divided pinnately.
The branching of the inflorescence is often the same as in the Juncaceæ, and supports the theory that these two orders are related. In Rhynchospora and others, the “spikelets” are really only “spike-like” and to some extent compound.
A. Scirpeæ. Hermaphrodite Flowers.
1. Spikelets cylindrical, the bracts arranged spirally (in many rows). The lower ones are often barren, each of the others supports a flower.—Scirpus (Club-rush). The spikelets are many-flowered; the perianth is bristle-like or absent, and does not continue to grow during the ripening of the fruit (Fig. [286] A). Closely allied to this is Heleocharis, with terminal spikes.—Eriophorum (Cotton-grass) differs chiefly in having the perianth-hairs prolonged, and forming a bunch of white, woolly hairs (Fig. [284] B).