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41. PARKINSONIA L. 
Somewhat spinescent shrubs or trees, with bipinnate leaves, 1 or 2 
pairs of pinnw, small leaflets, yellow or whitish flowers on slender ped- 
icels in short loose axillary or terminal racemes, equal sepals, and a 
short-stipitate flat linear to linear-oblong veined thin coriaceous pod, 
which is usually more or less torulose and compressed between the 
seeds. 
* Leaflets usually very numerous upon a much-elongated flattened rhachis. 
1. P. aculeata L. A small tree, glabrous throughout, the slender branches often 
pendulous: spiny petioles 12 to 24 mm. long or less, bearing 1 or 2 pairs of pinne 
near the base or these wanting; leaflets very small, oblong, scattered upon a broad 
rhachis 15 to 45 cm. long; stipules spinescent: racemes axillary, 7.5 to 15 em. long: 
petals yellow: pod attenuate at each end and contracted between the distant seeds, 
1 to 5-seeded, 5 to 25 cm. long.—Throughout southern and western Texas. Often cul- 
tivated for ornament and known as ‘ retama.” 
** Pinne short and leaflets few on a terete rhachis. 
2, P. Torreyana Watson. A small tree, 6 to 9 m. high, with light green and smooth 
bark; younger branches and leaves sparingly pubescent : leaflets 2 or 3 pairs, oblong, 
obtuse, narrower towards the scarcely oblique base, glancous, 4 to 6 mm. long: 
racemes terminating the branches, with rather long pedicels jointed near the middle: 
petals bright yellow, a prominent gland on the upper one: pod acute, scarcely or de- 
cidedly contracted between the very thick seeds, 2 to 8-seeded, 5 to 7.5 cm. long, with 
a double groove along the broad ventral suture.—A species of the Arizona region, 
found by Nealley in Hidalgo County. The “palo verde” of the Mexicans. Usually 
naked, as the leaves are early deciduous. 
3. P. florida Watson. <A species of the Mexican side of the Rio Grande Valley, and 
undoubtedly to be found as well in Texas. It very much resembles P. Torreyana, but 
can be easily distinguished by its sessile axillary racemes, pods with a narrow acute 
margin on the ventral side, and somewhat smaller leaflets. 
4, P. Texana Watson. A much branching shrub 6 to 15 dm. high, with very rigid 
divaricate and flexuose branches which are usually armed throughout with short and 
spreading axillary spines: leaflets 1 or 2 pairs, oblong-obovate, retuse, 4 to 6 mm. 
long: flowers solitary in the axil of a spine or somewhat racemose at the extremity 
of some of the branches: pod pubescent, about 2-seeded.—Abundant along the Rio 
Grande from El Paso down, often forming dense thickets. 
42. CISALPINIA L. 
Usually prickly shrubs or trees, with abruptly bipinnate leaves, race- 
mose or corymbose flowers, unequal sepals, and sessile unarmed flat 
pods. 
1. C. pulcherrima Swartz is common in cultivation in Texas, said to have been 
introduced from Mexico. It is a prickly shrub with obovate leaflets and very showy 
orange-colored and variegated flowers, the petals having long stipe-like claws and 
being handsomely fringed. 
43. GLEDITSCHIA L. (Honry-Locust.) 
Thorny trees, with abruptly once or twice pinnate leaves, inconspic- 
uous greenish and polygamous flowers in small spikes, 3 to 5 calyx- 
lobes, petals and stamens, and a flat 1 to many-seeded pod. 
