302 NYCTAGINACE.E. (FOUR-O'CLOCK FAMILY.) 



2. OXYBAPHUS, Vahl. 



Calyx with a very short tube and a bell-shaped (rose or purple) deciduous 

 limb, plaited in the bud. Style filiform : stigma capitate. — Herbs, with very 

 large and thick perennial roots, and mostly clustered small flowers. Ours ail 

 have pubescent fruit and involucres 3 to 5-flowered. 



1. O. nyctagineus, Sweet. Nearly smooth: stem repeatedly forked: 

 leaves all petioled, varying from ovate or somewhat heart-shaped to lanceolate- 

 fruit rather hirsute. — From Illinois, Wisconsin, aud the Upper Missouri to 

 Texas and New Mexico. 



Var. Cervantesii, Gray. Branches and involucres viscid-pubescent or vil- 

 lous : leaves much thicker, cordate or subcordate at base. — Bot. Mex. Bound. 

 174. S. Colorado and southward. 



Var. oblongifolius, Gray. Leaves ovate-lanceolate or oblong, not cordate. 

 — Loc. cit. Near Denver and southward. 



2. O. hirsutus, Sweet. One foot high, very densely pilose, with long, 

 spreading, articulated hairs: leaves lanceolate, the lower short-pet ioled : involucre 

 pubescent-tomentose : fruit hirsute. — From the Saskatchewan to Colorado and 

 W. Texas. 



3. O. angustifolius, Sweet. One to six feet high, glabrous except the 

 peduncles and involucres which are pubescent : leaves linear, usually elongated, 

 glaucous : fruit hoary-pubescent. — From Iowa and Minnesota to S. Idaho and 

 southward to W. Texas and Mexico. 



3. ALLIONXA, L. 



Perianth with an oblique 4 to 5-lobed limb. Fruit ovate, compressed, 

 smooth and convex on the inner side. — Annual or perennial herbs, with oppo- 

 site very unequal leaves, and axillary pedunculate flowers. 



1. A. inearnata, L. Stems slender, branching, prostrate: pubescence 

 viscid, short or floccose : leaves ovate: lobes of the involucre concave: peri- 

 anth rose-colored or white. — From S. Colorado to Texas, and westward to 

 S. California. 



4. ABRONIA, Juss. 



Tube of the perianth elongated, and the limb of 5 (or 4) obcordate or emar- 

 ginate segments. Stamens unequal, adnate to the tube. Fruit coriaceous 

 or indurated, 1 to 5-winged, mostly reticulately veined, enclosing a smooth 

 cylindrical akene. — Often prostrate, and usually more or less viscid-pubescent, 

 with thick opposite unequal leaves, and elongated axillary and terminal pedun- 

 cles : flowers usually very fragrant and showy. 



* Wings (if any) coriaceous, lateral and not completely encircling the fruit. 



1. A. fragrans, Xutt. Stems ascending : leaves oblong or ovate, truncate 

 or more or less enneate at base : peduncles elongated : bracts of the involucre 

 large, broadly ovate, white and scarious : fruit narrowly 1 to 2-winged, not 

 crested. — From Iowa to Salt Lake Valley and southward to Arizona and 

 New Mexico. 



