240 NORTH AMERICAN FLORA [VoLumE 21 
apex, thin, bright-green, minutely puberulent or in age glabrate, minutely ciliolate; inflores- 
cence of numerous dense terminal headlike cymes, these subtended by leaves or narrow bracts, 
the peduncles 3 mm. long or usually shorter; involucre campanulate, 1-1.5 cm. long, densely 
puberulent, slightly if at all viscid, the lobes about as long as the tube, narrowly to broadly 
triangular, very acute to long-attenuate; perianth white tinged with pink or purple, 10-14 cm. 
long, sparsely and minutely puberulent outside, the tube very slender, 2 mm. in diameter, 
abruptly expanded into a shallowly 5-lobed limb 2.5-3 cm. broad; stamens 5, exserted 3 cm. 
or less; fruit oblong-ellipsoid, 8 mm. long, 5 mm. in diameter, constricted at both ends, dark- 
brown, obtusely tuberculate, puberulent. 
TYPE Locauity: Mexico. 
DisrRisurion: Southern Arizona to western Texas, Coahuila, and Sonora. 
DOUBTFUL SPECIES 
MIRABILIS HYBRIDA Lepel. Ann. Mus. Paris 8: 481. 1806. (Mirabilis cordata Brouss.; 
R. & §. Syst. Veg. 4:2. 1819.) A form described from cultivated material, thought to be a 
hybrid between M. Jalapa and M. longiflora. It has been stated that the plant is found in 
the natural state, but no such specimens have been seen by the writer. 
MriraBitis OaxacaE Heimerl (Sitz.-ber. Akad. Wiss. Wien 93: 234, hyponym. 1886) 
Beitr. Syst. Nyct. 20. 1897. Said to be “a subspecies or variety with the flowers long- 
tubular, the limb of the perianth narrow, the involucres short, the fruit more oblong (than in 
M. Jalapa) * * * collected by Franco about Oaxaca in southern Mexico.” 
VI. ABRONIEAE. Herbs. Leaves opposite. Flowers perfect, capitate, 
the head surrounded by an involucre of distinct bracts; perianth corolla-like, 
the free portion withering and persistent or deciduous, the lobes induplicate- 
valvate. Stigmalinear. Anthocarp coriaceous, eglandular. Embryo curved, 
the inner cotyledon abortive. 
25. TRIPTEROCALYX (Torr.) Hook. Jour. Bot. & Kew Misc. 
5: 261. 1853. 
Abronia § Tripterocalyx Torr. in Frém. Rep. 92. 1843. 
Gren Nutt.; A. Gray, Am. Jour. Sci. II, 15: 319, as synonym. 1853. Not Cycloptera Endl. 
1 
Apaloptera Nutt.; A. Gray, Am. Jour. Sci. IT. 15: 319, as synonym. 1853 
Tripteridium Torr.; Britt. & Brown, Ill. Fl. ed. 2. 2: 33, assynonym. 1913. 
Succulent annual herbs, erect, decumbent, or procumbent, branched, more or less pubes- 
cent. Leaves opposite, those of a pair unequal, long-petiolate, the blades broad, entire or 
slightly sinuate. Flowers perfect, capitate, the heads many-flowered, surrounded by an 
involucre of numerous distinct thin bracts, the bracts unchanged after anthesis; perianth 
corolla-like, tubular-funnelform, the tube slender, clongate, constricted above the ovary, 
the limb narrow, 4- or rarely 5-lobed, the lobes obovate or obcordate, emarginate or bilobate, 
induplicate-plicate. Stamens 4 or rarely 5; filaments capillary, unequal, connate at the base, 
united above with the perianth-tube; anthers linear-oblong, included. Ovary ovoid; style 
filiform; stigma fusiform, included. Anthocarp fusiform, with 2-4 broad thin reticulate- 
veined vertical wings, these completely encircling the body and extended above and below it, 
the body coriaceous, spongious, or indurate, often costate between the wings. Seed with a 
thin testa adherent to the pericarp; one of the cotyledons broad and enclosing the farinaceous 
endosperm, the other obsolete; radicle slender, elongate, descending. 
Type species, Abronia micrantha Torr. 
Body of the fruit sparsely villous, coarsely transverse-costate, the veins of the 
2 wings much thickened; bracts 6-10 mm. long; perianth 2-2.5 cm. long. 1. T. Crux-Maltae. 
Body of the fruit glabrous or sparsely puberulent, longitudinally costate or 
obscurely transverse-veined, the veins of the 3 or rarely 4 wings slender. 
Perianth about 1.5 cm. long, the limb greenish. 
Body of the fruit longitudinally costate; peduncles elongate, often 
longer than the subtending leaves; perianth glabrous or obscurely 
puberulent. 2. T. pedunculatus. 
