80 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
be placed in the same section with A. muricata on account of the peculiar 
structure of its rigid coriaceous leaves, which are devoid of the peculiar pits in 
the axils of the lateral nerves, characteristic of the section Euannona; and it is 
separated from Annona purpurea and its allies not only by its leaves but also by 
its inner petals, which are not imbricate and overlapping. The author has 
consequently been obliged to place it in a section apart, for which he proposes 
the name Psammogenia, since it comes forth from the sands of arid plains. 
EXPLANATION OF PLATE 11.—Photograph of type in the De Candolle Herbarium, show- 
ing flower bud, flower from which the petals and stamens have been removed, with the 
tips of the calyx lobes broken off, a number of loose stamens, an inner petal, and two 
outer petals. All natural size. Negative by H. K. Sloat. 
Annona purpurea Moc. & Sessé, 
Anona purpurea Moc. & Sessé in Dunal, Monogr. Anon. 64. pl. 2. 1817. 
Anona manirote H. B. K. Noy. Gen. & Sp. 5:59. 1821. 
Section Ulocarpus. A small or medium-sized deciduous tree with spreading 
branches and very large short-petioled leaves; older branches brown, bearing 
prominent leaf scars; young branches clothed at first with fulvous or ferrugine- 
ous tomentum, but soon glabrate; leaves membranaceous at first, conduplicate, 
their parenchyma more or less bullate, at length subcoriaceous and undulate, 
green and smooth above with the impressed midrib and lateral nerves (20 to 25 
on each side) very prominent beneath, ferrugineous-pubescent on both faces; 
petioles 5 to 8 mm. long and 3 to 4 mm. thick; blades oblong-elliptical or oblong- 
obovate to oblong-lanceolate, acuminate above, the apex usually acute, but some- 
times obtuse or retuse, obtusely cuneate or rounded at the base, 20 to 30 cm. long 
and 10 to 14 cm. broad; flowers very large, solitary, extra-axillary, appearing at 
the same time as the new leaves, usually inclosed at first by an involucre com- 
posed of 2 sessile acuminate bracts, these with marcescent apex and persistent 
base resembling a second, or outer, calyx; peduncle very short and thick, at 
length woody ; calyx 8-lobed, the lobes broadly ovate or deltoid, acute or obtuse 
at the apex, ferrugineous-velvety on the outside; corolla composed of 6 petals in 
2 series, increasing in size after anthesis, the 3 outer ovate or ovate-lanceolate, 
very thick, valvate, concave, usually acuminate but sometimes obtuse at the 
apex, ferrugineous-velvety on the outside, stained with deep purple within; 
inner petals somewhat smaller and thinner, imbricate, ovate or subrotund, 
concave, forming a domelike covering over the essential parts, whitish on the 
outside, purple within; receptacle conoid or hemispherical, densely clothed 
with short, stiff, straight, light brown hairs; stamens numerous, about 5 or 6 
mm. long, ¢club-shaped, with the connectives expanded and swollen into brown 
velvety heads so closely crowded together as to form a continuous covering above 
the linear parallel brown pollen sacs; carpels 5 or 6 mm. long, with the ovary 
about 2.5 to 3 mm. long, sulcate on the inside, clothed with fine light brown 
sericeous hairs, surmounted by a prism-shaped style of equal length terminating 
in a capitate pale brown velvety stigma; fruit large, broadly ovoid or spheroid, 
15 to 20 ecm. in diameter, bearing numerous rigid pyramidal protuberances and 
clothed with brown feltlike tomentum, the protuberances grooved on the 
ventral side and usually terminating in a hook directed toward the peduncle; 
seeds large, obovate, more or less compressed and marginate, 28 to 30 mm. long, 
14 to 18 mm. broad, and 9 mm. thick, with a smooth chestnut brown testa 
covered when fresh by a thin membranous closely adhering envelope (aril ?) 
