426 NYCTAGINACE^E. (FOUR-O'CLOCK FAMILY.) 



Embryo monocotyledonous. Low herbs, with thick opposite petioled une- 

 qual leaves, axillary or terminal peduncles, and showy flowers in solitary 

 heads. (Xame from a&pos, yraaful.) 



1. A. fragrans, Xntt. More or less viscid-pubescent, from a perennial 

 root; leaves oblong or ovate, truncate or cuneate at base; involucre conspic- 

 uous, of broad ovate white and searious bracts; flowers white, fragrant, 4 - 1 0" 

 long; fruit coriaceous, obpyramidal, with narrow undulate coarsely reticulated 

 wings. From W. Iowa to Utah and N. Mex. 



ORDKR 85. ILLECEBRACEJE. (KNOTWORT FAMILY.) 



Herbs, with mostly opposite and entire leaves, searious stipules (except 

 in Sclevanthus), o 4-5-toothcd or -parted herbaceous or coriaceous persis- 

 tent calyx, no petals, stamens borne on the calyx, as many as the lobes and 

 opposite them or feiuer, styles 2 and often united, and fruit a 1-seeded 

 utricle. Seed upon a basal funiele, the embryo (in ours) surrounding 

 the mealy albumen. Small diffuse or tufted herbs, with small greenish 

 or whitish flowers in clusters or dicliotomous cymes. 



1. Aiiychia. Stamens on the base of the 5-parted awnless calyx. Styles hardly any. 



2. Paronychiat 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. 



3. Sclei-aiithus. Stamens borne on the throat of the indurated 5-cleft and pointless calyx. 



Stylos - Stipules none. 



1. A "N Y C H I A, Michx. FORKED CHICKWEED. 



Sepals 5, scarcely concave, indistinctly mucronate on the back, greenish. 

 Stamens 2-3, rarely 5. Stigmas 2, sessile. Utricle larger than the calyx. 

 Radicle turned downward. Small, many times forked annuals, with small 

 stipules, and minute flowers in the forks, produced all summer. (Same deri- 

 vation as the next genus.) 



1. A. dichotoma, Michx. More or less pubescent, short-jointed, low and 

 spreading ; leaves somewhat petioled, mostly very narrowly lanceolate or ob- 

 lanceolate ; flowers nearly sessile and somewhat clustered. Mostly in open 

 places, N. Eng. to Fla., west to Minn, and Ark. 



2. A. Capillacea, DC. Smooth, lonycr-jointfd, slender and erect ; leaves 

 thinner, broader and longer (5-15" long) ; JJoirers more stalked and diffuse. 

 (A. dichotoma, var. capillacea, Torr.) Dry woodlands, same range as the 

 last, but more abundant northward. 



2. PARONYCHIA, Touru. WHITLOW-WORT. 



Sepals 5, linear or oblong, concave, awned at the apex. Petals (or stami- 

 nodia) bristle-form, or minute teeth, or none. Stamens 5. Style 2-cleft at 

 the apex. Utricle enclosed in the calyx. Radicle ascending. Tufted herbs 

 (ours perennial), with dry and silvery stipules, and clustered flowers. (Greek 

 name for a whitlow, and for a plant thought to cure it.) 



1. P. argyrocoma, Nutt. Forming broad tufts, branched, sprea d ing; 

 leaves linear (%' long) ; flowers denseli/ clustered, surrounded by conspicuous 

 large silvery bracts; calyx hairy, short-awned ; petals mere teeth between the 



