1. O. nyctagíneus, Sweet. Nearly smooth; stem becoming repeatedly forked, 1–3° high; leaves all petioled (except the uppermost reduced ones), from broadly ovate to lanceolate, rounded or cordate or cuneate at base; inflorescence loose and but slightly pubescent, the peduncles slender (at first solitary in the axils); fruit oblong-obovate, 2´´ long, rather acutely angled.—Minn. and Wisc. to Tex. and La.; rare escape from gardens in E. Mass. and R. I.
2. O. hirsùtus, Sweet. More or less glandular-hirsute, especially about the nodes and the usually contracted inflorescence, 1–3° high; leaves lanceolate to linear-lanceolate, sessile and cuneate at base or narrowed to a short petiole; stamens often 5; fruit with thickened obtuse angles.—Plains of the Sask. to Wisc., Iowa., Neb., and Tex.
3. O. angustifòlius, Sweet. Often tall, glabrous except the more or less hirsute peduncles and involucres; leaves linear, thick and glaucous, often elongated (2–6´ long); fruit as in the last.—Minn. to Tex., and westward.
2. ABRÒNIA, Juss.
Involucre of 5–15 distinct bracts, enclosing numerous sessile flowers. Calyx salver-form, with obcordate lobes. Stamens 5, included, adnate to the calyx-tube. Style included; stigma linear-clavate. Perfect fruit 3–5-winged. Embryo monocotyledonous.—Low herbs, with thick opposite petioled unequal leaves, axillary or terminal peduncles, and showy flowers in solitary heads. (Name from ἁβρός, graceful.)
1. A. fràgrans, Nutt. More or less viscid-pubescent, from a perennial root; leaves oblong or ovate, truncate or cuneate at base; involucre conspicuous, of broad ovate white and scarious bracts; flowers white, fragrant, 4–10´´ long; fruit coriaceous, obpyramidal, with narrow undulate coarsely reticulated wings.—From W. Iowa to Utah and N. Mex.
Order 85. ILLECEBRÀCEÆ. (Knotwort Family.)
Herbs, with mostly opposite and entire leaves, scarious stipules (except in Scleranthus), a 4–5-toothed or -parted herbaceous or coriaceous persistent calyx, no petals, stamens borne on the calyx, as many as the lobes and opposite them or fewer, styles 2 and often united, and fruit a 1-seeded utricle. Seed upon a basal funicle, the embryo (in ours) surrounding the mealy albumen.—Small diffuse or tufted herbs, with small greenish or whitish flowers in clusters or dichotomous cymes.
1. Anychia. Stamens on the base of the 5-parted awnless calyx. Styles hardly any.
2. Paronychia. Stamens on the base of the 5-parted calyx; the sepals hooded at the summit and bristle-pointed. Style 1, 2-cleft at the top.