038 



TREES OF NOKTH AMERICA 



grandular-punctate, the terminal the largest. Flowers regular, perfect, on slender bibracte- 

 olate pedicels, in terminal or axillary panicles; calyx 3 or 4-parted, the divisions imbricated 

 in the bud, slightly united at base, persistent; petals 3 or 4, imbricated in the bud, hypogy- 

 nous, oblong, concave, glandular-punctate, reflexed at maturity; stamens as many as the 

 petals inserted under the disk; filaments shorter than the petals, slightly flattened, glabrous; 

 anthers ovoid, cordate at base, attached on the back below the middle; disk free, cup-shaped, 

 erect, subcorrugated, with a sinuate margin, 4-lobed, the lobes entire or crenate and opposite 

 the petals; ovary minute, sessile, depressed, 3 or 4-lobed, glandular-verrucose or minutely 

 pilose, the lateral lobes slightly compressed, 4-celled; styles united into a single slender 

 column crowned by the globose 3-4-lobed stigma; ovules collateral, anatropous. Fruit 

 obconic, composed of 3 or 4 dry woody 1-seeded indehiscent carpels with a cartilaginous 

 endocarp and with a prominent horizontal wing, separating at maturity. Seed linear- 

 oblong, seed-coat crustaceous, fragile, black; cotyledons straight, obtuse. 



Helietta is distributed from the valley of the lower Rio Grande in Texas to Brazil and 

 Paraguay. Four species are recognized, one species extending across the Rio Grande 

 into western Texas. 



The generic name is in honor of Lewis Theodore Helie (1804-1867), a distinguished 

 French physician. 



1 . Helietta parvifolia Benth. 



Leaves l'-2' long, with a stout slightly club-shaped petiole, at first puberulent, soon 

 becoming glabrous, and oblong or narrow-obovate leaflets rounded or sometimes slightly 



Fig. 581 



emarginate at apex, gradually and regularly contracted at base, entire or slightly and re- 

 motely crenulate-serrate, yellow-green and lustrous above, paler below, conspicuously 

 marked by black glandular dots, the terminal leaflet %-l\' long, sometimes \' wide, and 

 nearly twice as large as the others; persistent on the branches until early spring. Flowers 

 appearing in April and May, on slender pedicels covered at first like the petioles and calyx 

 with short dense pubescence, with minute acuminate early deciduous bracts, in dichoty- 

 mously branched subsessile panicles on branchlets of the year from the axils of the upper 

 leaves; petals 4, white, ovate, \' long, with scattered hairs on the outer surface, and thin 

 scabrous margins, and four or five times longer than the 4 calyx-lobes; stamens 4; ovary 

 4-lobed, glandular-punctate like the slender style. Fruit ripening in October, oblong, '-$' 

 long, with a rigid broad-ovate sometimes slightly falcate wing rounded at apex, \' long, 

 and conspicuously reticulate- veined. 



A slender tree, 20-25 high, with a trunk 5'-6' in diameter, rather erect branches form- 



