358 ffOUK-O'OLOCK FAMILY. 



III. APETALOUS DIVISION. 



Includes the families with flowers destitute of corolla, 

 or of both corolla and calyx. Various apetalous genera 

 and species are, however, distributed through the poly- 

 petalous and monopetalous families, where they evidently 

 belong. These three divisions are entirely artificial. 



XCI. NYCTAGINACEJJ, FOUR-O'CLOCK FAMILY. 



Here represented by a few herbs with tubular or funnel- 

 form calyx colored like a corolla, and falling away from a per- 

 sistent lower portion which closes completely over the 1-celled 

 1-ovuled ovary and seed-like fruit, forming a hard and dry 

 covering which would be mistaken for a true pericarp. Sta- 

 mens 2-5, the long slender filaments hypogynous, but apt to 

 adhere somewhat to the sides of the calyx tube above. Embryo 

 coiled around some mealy albumen. (Lessons, Figs. 52-55.) 

 Ours are herbs, with opposite, simple, entire or wavy leaves, 

 and jointed stems, tumid at the joints. 



* Involucral bracts wholly distinct. 



1. ABRONIA. Flowers small, many in a peduncled umbel-like head surrounded by an 



Involucre of about 5 bracts. Calyx salver-shaped, with a slender tube, and a corolla- 

 like 5-lobed border, which is plaited in the bud, the lobes generally notched at the end. 

 Stamens 5 and style included. 



* * Involucral bracts united at the base. 



2. OXYBAPHUS. Flowers small, a few together surrounded by a 5-lobed involucre, 



which enlarges and becomes thin, membranaceous, reticulated, and wheel-shaped 

 after flowering. Calyx with a very short tube constricted above the ovary, expand- 

 ing into a bell-shaped 5-lobed corolla-like border, open only for a day. Stamens 

 (mostly 3) and slender style protruding. Fruit (persistent base of calyx) akene-like, 

 strongly ribbed. 



8. MIRABILIS. Flower large, in the common species only a single one in the cup-shaped 

 5-cleft green involucre, which thus exactly imitates a calyx, as the tubular funnel- 

 shaped or almost salver-shaped delicate calyx does a corolla. 5 stamens, and especially 

 the style (tipped with a shield-shaped stigma) protruded. Fruit ovoid, smooth and 

 nearly even. 



1. ABRONIA. (Greek: graceful.') Western North American herbs, 

 cultivated for ornament ; flowers all summer. 2/ 



* Flowers rose-purple. 



A. umbel/ata, Lam. Cal. ; prostrate slender stems, ovate-oblong slender 

 oetioled leaves, and flowers open by day, the involucre of small bracts. 



