STANDLEY — ALLIONIACEAE OF MEXICO. 381 



Stigma spherical or hemispherical; inner 

 cotyledon not abortive; lower part 

 of the perianth often with muci- 

 laginous glands; anther cells al- 

 most spherical. 

 Stamens 9 to 17 ; peduncles lengthen- 

 ing in age and penetrating into 



the earth 10. Okenia (p. 396). 



Stamens 1 to 5; peduncles slightly if at 



all elongated in age and not 



penetrating into the earth. 



Anthocarp with 5 or fewer thin, 



scarious wings. (Perianth 



almost campanulate to sal- 



verform with a long tube; 



involucre of a few small and 



inconspicuous bracts) 11. SeIinocarpus (p. 398). 



Anthocarp never with thin, scari- 

 ous wings. 

 Anthocarp lenticular, usually with lateral, incurved 

 teeth. (Flowers in 3's surrounded by an invo- 

 lucre which is 3-parted almost to the base) 12. Wedeliella (p. 399). 



Anthocarp never lenticular nor with marginal teeth, 

 usually ob pyramidal or ellipsoidal. 

 Flowers in many-flowered heads surrounded by an 

 involucre of distinct, lanceolate bracts. 

 (Perianth salverform with a long tube; sta- 

 mens long-exserted, usually 5) 13. Nyctaginia (p. 400). 



Flowers not in many-flowered heads surrounded by 

 an involucre of distinct bracts, usually 1 to 

 3 or sometimes 10 together, each flower sub- 

 tended by 1 to several bracts or the bracts 

 united . 

 Involucre gamophyllous. 



Anthocarp constricted at the base, hence 

 obovoid, prominently 5-ribbed; in- 

 volucre enlarged and membranous 

 in fruit. (Involucre 1 to 5-flowered ; 

 perianth campanulate or nearly 



bo) - 14. Allionta (p. 401). 



Anthocarp oblong or ellipsoidal, smooth 



or somewhat 5-angled, but never 



prominently 5-ribbed; involucre not 



noticeably enlarged in fruit. 



Involucres 3 to 10-flowered . (Perianth 



with a long but thick tube) 15. Quamoclidion (p. 410). 



Involucres 1-flowered. 



Perianth campanulate; antho- 

 carp smooth lfi. Hespeeonia (p. 411). 



Perianth salverform, often with a 

 long and slender tube; antho- 

 carp slightly 5-angled 17. Mirabilis (p. 413). 



Involucre polyphyllous (the bracts often un- 

 equal). 



