8 NATURAL HISTORY OF PLANTS. 
petiolate leaves. Some twenty-five species' of them are enumerated, 
abounding principally in America, but this genus is found in all the 
warm regions of the globe. 
Abronia has the inflorescence of Nyctaginia, with an involucre 
generally of five leaves, and some differences in the perianth and the 
fruit. The first is hypocrateriform, with a tube swollen at the base, 
and a limb spreading more or less obliquely, and separated into 
lobes, equal or slightly unequal The androceum is formed of five 
unequal stamens, included, and adhering to the perianth by their 
filaments. The style is claviform or taper- 
ing towards its stigmatiferous apex. The fruit 
(fig. 13) is narrow and elongated. The 
basilar portion of the perianth, which persists 
round it, dilates as in Selinocarpus, into yet 
more fully developed membranous and veined 
wings. The embryo has generally only one 
cotyledon, the interior aborting. The ddronias 
ey a are creeping herbs, natives of the tempe- 
Fruit, rate parts of North America. Half a dozen 
have been described, which are probably only 
varieties of one and the same species.‘ Their leaves are opposite, 
long-petiolate and unequal; the pedunculate inflorescence is ter- 
minal, although seemingly lateral or axillary. 
Pisonia’ (figs. 14-17) has regular polygamous flowers. In certain 
species of them, which are hermaphrodite, is found a perianth forming 
Abronia cycloptera. 


1L., Spee. 4.—W., Spec., 1, 19; Phyt.,i.n.  Mém. Pétersb.,x.; Descr. Pl. Nov.-Calif., 281.— 
3,—Vaut, Enum., i. 287.—Lour., Fl. Cochinch., Brntu., Voy. Sulph., Bot., 43.—Torr., in Frem. 
20.—H. B. K., Nov. Gen. et Spec., ii. 216.— first Rep., 96; in Emor. Rep., 149; in Slansb. 
Forsr., Prodr., n. 5.—Laa. et Ropr., in Ann. Expl. Rep., 395.—A. Gray, Brief Char,.., 5. 
Cienc. Matr. (1801), 256.—Ricw., in Act. Soc. 5 Prum., Icon. (ed BuRM.), t. 227; Amer, 
Hist. Nat. Par., i, 105.—R. Br., Prodr., 422. 7, t. 11 (nec Rovrs.).—L., Gen, n. 897.— 
—C, Gay, Fl. Chil., v. 209.—A. Gray, Brief  ADANS., Fam. des PL, ii. 265.—J., Gen., 91; in 
Char,.., 7.—WatLP., Ann. i. 559; ili, 298; v. Ann. Mus., ii. 275.—GæRIN., Fruct., i. t. 76— 
722. Porr., Dict., v. 346; Suppl, iv. 419.—LAMK., 
2 J., Gen., 448.—GÆRTIN., Fruct., iii. 181,t. ZUL, t. 861.—Enpu., Gen., n. 2012.—CHors., 
214.—-Lamx., Dict., viii. 85; JU, t. 105— Prodr., 440.—Torrubia VELLOZ., Fl. Flum., iii. 
Expt., Gen., n. 2002.—Cuors., Prodr., 435, n. t. 150.—Bessera VELLOZ., op, cit., iv. t. 2.— 
6.—Tricratus Lugsr., Diss., e. ie.—Cycloptera  Pallavia Vezxoz., op. cit., iv. t. 12.— Columella 
Nurt., mss.—Apaloptera Nurr., mss, (ex A. VeELLOzZ., op. cit. iv. t. 17.—Tragularia Kan, 
Gray). (ex Roxs., Fl. Ind., ii. 345).—Calpidia Dur.- 
% In this case the exterior ones are the most u., Hist. Pl. Il. Afr, Austr., 23, t. 8 (incl. : 
developed. Cephalotomandra Karst. et 'Trr., Neea R, et 
* Hoox., in Bot. Mag., 2879; Exot. Fl,, t. Pav., Vieillardia Ap. Br. et GR.). 
193, 194; F1. Bor.-Amer., ii, 125.—Escu., in 
