LEGUMINOSE. SILVA OF NORTH AMERICA. 81 
CERCIDIUM. 
FLoweErs perfect, in short axillary racemes; calyx disciferous, 5-lobed, the lobes 
valvate in estivation; petals 5, nearly equal, imbricated in estivation; ovary many- 
ovuled. Legume linear-oblong, compressed, 2-valved, conspicuously nerved on the ven- 
tral suture. Leaves abruptly bipinnate. 
Cercidium, Tulasne, Arch. Mus. Paris, iv. 133.— Bentham Rhetinophloum, Karsten, Fl. Columb. ii. 25. 
& Hooker, Gen. i. 570. — Baillon, Hist. Pl. ii. 172. 
Trees or shrubs, with stout tortuous branches covered with bright green bark and armed with 
slender straight axillary spines. Leaves alternate, abruptly bipinnate, early deciduous, petiolate; pinne 
two or occasionally three, four to eight-foliolate ; stipules inconspicuous or wanting’; leaflets ovate or 
obovate, without stipels. Flowers in short graceful few-flowered axillary racemes solitary or fascicled. 
Bracts minute, membranaceous, early deciduous. Calyx contracted into a long stipe jointed on the 
slender pedicel, membranaceous, shortly campanulate, persistent, with equal acute deciduous lobes 
reflexed at maturity, their margins scarious, slightly revolute. Petals orbicular or oblong, unguiculate, 
bright yellow, the upper one broader and longer clawed than the others, a little auricled at the base of 
the blade, the claw (in the North American species) conspicuously glandular at the base. Stamens ten, 
inserted with the petals on the margin of the disk, free, slightly declinate, exserted ; filaments filiform, 
pilose below, the upper one (in the North American species) enlarged at the base and gibbous on the 
upper side; anthers uniform, ovate, attached on the back below the middle, versatile, two-celled, the 
cells opening longitudinally. Ovary short-stalked, inserted at the base of the calyx-tube, glabrous or 
covered with long hairs; style slender, involute, infolded in the bud and terminated by a minute 
stigma ; ovules suspended from the angle of the ovary opposite the posterior petal, superposed, ana- 
tropous, the micropyle superior. Legume linear-oblong, compressed or somewhat turgid, straight or 
slightly contracted between the seeds, thickened on the margins, that of the ventral suture acute or 
slightly grooved, tipped with the remnants of the style, tardily dehiscent, two-valved, the valves 
membranaceous or subcoriaceous, obliquely veined. Seeds suspended longitudinally on long slender 
funicles, ovate, compressed, the minute hilum near the apex; testa thin, crustaceous. Embryo com- 
pressed, surrounded by a thin layer of horny albumen; cotyledons oval, flat, rather fleshy ; radicle very 
short, erect, near the hilum. 
Cercidium is confined to the warmer parts of the New World, where it is distributed with four or 
five species’ from the southern borders of the United States through Mexico, Central America, and 
Venezuela to Mendoza. Three species occur in the territory of the United States, two being small trees, 
and the third, a native of western Texas, a low intricately branched and often prostrate shrub.’ 
The North American species produce rather hard wood which is sometimes used as fuel, but the 
genus is not known to be otherwise useful to man. 
The generic name, from xepxidiov, refers to the fancied resemblance of the legume to a weaver’s 
instrument of that name. 
1 Walpers, Rep. v. 552; Ann. iv. 594. — Karsten, Fl. Columb. Parkinsonia Texana, Watson, Proc. Am. Acad. xi. 136. — Coul- 
iv. 25, t. 113 (Rhetinophleum). — Hemsley, Bot. Biol. Am. Cent. ter, Contrib. U. S. Nat. Herb. ii. 94 (Man. Pl. W. Texas). 
i. 326. The flowers of Cercidium Texanum are readily distinguished 
2 Cercidium Texanum, Gray, Smithsonian Contrib. iii. 58; v.50 from those of the other North American species by the long white 
(PL. Wright. i., ii). — Walpers, Ann. 1. c.— Torrey, Bot. Jfezx. hairs which clothe the ovary. 
Bound. Surv. 59. 
