1. ELATÌNE, L. Water-wort.
Sepals 2–4, persistent. Petals 2–4, hypogynous. Stamens as many, rarely twice as many, as the petals. Styles, or sessile capitate stigmas, 2–4. Pod membranaceous, globose, 2–4-celled, several–many-seeded, 2–4-valved; the partitions left attached to the axis, or evanescent. Seeds cylindrical, straightish or curved, marked by both longitudinal and transverse lines.—Dwarf glabrous plants, usually rooting at the nodes, aquatic or terrestrial. (A Greek name for some obscure herb.)
1. E. Americàna, Arn. Tufted, 1´ high; leaves obovate, obtuse, 1–3´´ long; flowers sessile, rarely opening in the aquatic form; sepals, petals, stamens, and stigmas 2, rarely 3; seeds 5 or 6 in each cell, rising from the base, marked by 9 or 10 longitudinal lines and 20–30 crossbars.—Margin of ponds, etc., N. H. to Ill., Va., and southwestward. Pod very thin and delicate; the seeds large in proportion, straightish.
2. E. triándra, Schkuhr. Leaves oblanceolate or nearly lanceolate; petals and stamens commonly 3; seeds more slender, covering the axis.—Ponds, Ill., Neb., and westward. (Eu.)
3. E. brachyspérma, Gray. Leaves oblong or oval with narrowed base; flowers mostly dimerous; seeds short-oblong, with 6 or 7 longitudinal lines and 10–12 crossbars.—Ill. and southwestward.
Order 18. HYPERICÀCEÆ. (St. John's-wort Family.)
Herbs or shrubs, with opposite entire dotted leaves and no stipules, regular hypogynous flowers, the petals mostly oblique and convolute in the bud, and many or few stamens commonly collected in 3 or more clusters or bundles. Pod 1-celled with 2–5 parietal placentæ, and as many styles, or 3–7-celled by the union of the placentæ in the centre; dehiscence mostly septicidal.—Sepals 4 or 5, imbricated in the bud, herbaceous, persistent. Petals 4 or 5, mostly deciduous. Styles persistent, at first sometimes united. Seeds numerous, small, anatropous, with no albumen. Embryo cylindrical.—Plants with a resinous juice, dotted with pellucid or dark glands, usually smooth. Leaves mostly sessile. Flowers solitary or cymose.
[*] Petals oblique, convolute, yellow; hypogynous glands none.
1. Ascyrum. Sepals 4, in 2 very unequal pairs. Petals 4. Stamens many, distinct.
2. Hypericum. Sepals 5, alike. Petals 5. Stamens usually many and in 3 or 5 clusters.