This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
The habitat of this species is cultivated ground. The plant is like B. mollis. The panicle is oblong, blunt, erect, rigid. The spikelets are more or less compound, in dense, interrupted clusters. The upper palea is split to the base. The plant is 2-4 ft. high, flowering in June and July, and is a herbaceous annual or biennial.
The habitat of this grass is pastures, waste places. The plant is dark-green. There are leafy, barren shoots. The root is fibrous. The stems are bent below, ascending, hairless, flattened. The leaves are flat, the edges of the young leaves simply folded. The edges and upper surface are rough. The sheaths are smooth, flattened. There is a short ligule. The spike is simple (6-11 flowered), rigid, stout or slender, and 3-4 flowered. The rachis is smooth, channelled one side. The spikelets are smooth, shining. The empty glumes are shorter than the spikelet, ribbed, linear-lanceolate. The flowering glumes are linear to oblong, round, blunt (or awned), ribbed. The glume equals the lowest flower. The lower palea is awnless. The plant is 1-2 ft. high, flowering from June to October, and is a perennial.
(Bog and marsh plants may be otherwise described as moor and fen plants. Both require moist conditions, though some moorlands are drier and more allied to heaths. Fen or marsh plants are more allied to aquatic vegetation in requiring more or less partly submerged conditions. But both bog and marsh plants are allied in the fact that they nourish on a layer of peat, thick in the former, thin in the latter case. An essential difference is the character of the mineral salts, acid in the former, alkaline in the latter. Transitions from these states towards heath plants on the one hand, aquatic plants on the other, are to be found, and hence some plants occurring in this section may be found in either of the others.)
The habitat of this plant is the higher parts of mountains, alpine and subalpine bogs; and it is plentiful on wet rocks, and in swampy spots on moors. The plant is erect in habit. The stem is wiry, simple, naked, sometimes stoloniferous, more or less leafless. The leaves are twice ternate, chiefly radical, long-stalked. The leaflets are small, nearly rounded, bluish-green below, with blunt lobes. The flowers are few, in simple, terminal racemes, at first drooping, later erect. The ultimate flower-stalks are bent back in fruit. The purplish sepals are four. The stamens are pendulous, 18-20. The anthers are linear, apiculate. The capsule, an achene, is shortly stalked, curved, ribbed, tipped with the hooked style. The plant is 4-10 in. high, flowering in July and August, and is a herbaceous perennial.
The habitat of this plant is marshes and ditches, S. and W. England, shallow pools, and the plant is very rare. The plant is floating. The submerged leaves are loosely 3-forked (hence tripartitus), the segments slender, collapsing to some extent, the floating leaves small, deeply divided nearly to the base into 3 (hence also tripartitus), the segments rounded, 2-5 lobed, the central one as long as the lateral. The stipules are round, the upper free. The flower-stalk is slender, as long as the leaf-stalks, bent back at length. The flowers are white, very small, the petals not longer than the calyx. The stamens are 5-8, the stigma tapering. The receptacle is small and round. The carpels are few, inversely egg-shaped, swollen, with a small hairless beak. The plant is floating, flowering between May and August, and is a herbaceous perennial.