16 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
are acute and valvate and bear a keel or midrib on the back. The stamens 
terminate in a velvety, expanded connective tip and the hairy ovaries are 
grouped into a conoid gynecium. The flowers are fascicled in extra-axillary or 
cauliflorous clusters of two or three, like those of the section Chelonocarpus, 
Fic, 21.+-Annona acutifiora. 
Leaves and flowers. 
ural size. 
usually only 1 or 2 flowers of the cluster devel- 
oping fruit. Fruit (immature specimens only 
observed) resembling that of A. cherimola (fig. 
48, p. 41). The name of the section, which is 
included in Martius’s Acutiflorae, is suggested 
by the more or less fusiform flower-bud. 
Atractanthus seems to be intermediate between 
Phelloxylon and Chelonocarpus, resembling the 
former in its acute, valvate inner petals and the 
latter in its clustered peduncles. 
Group IV. ATTAE (CUSTARD APPLES). 
Section Attae Mart., in part.) 
Inner petals when present minute and scale- 
like, often not exceeding the stamens in length; 
outer petals linear or oblong, swollen and con- 
cave at the base, and usually keeled within or triquetrous above. This section 
includes the subsection Oblongiflorae, or Cherimoliac, of Martius, but excludes 
the Pilaeflorae, described above. 
KEY TO THE SECTIONS, 
Peduncles with amplexicaul leaflike bracts at the 
base; seeds with thick testa like the shell 
of a nut 
a 11. InaMa (p. 19). 
Peduncles without amplexicaul leaflike bracts at 
the base; testa of seeds thin. 
Leaves with thick conspicuous reticulating 
veins beneath between the _ lateral 
nerves 
re 12. Saxicena (p. 20). 
Leaves witb the veins not conspicuously re- 
ticulated beneath. 
Fruit thick-shelled when mature, with 
Fruit 
the areoles separated by raised 
ridges; pulp aromatic, mango-fla- 
vored, watery 
thin-skinned when mature, with 
the areoles more or less gibbous. 
tuberculate or smooth, sometimes 
separated by impressed lines; pulp 
sweet or sweet-acidulous, some- 
times insipid, custard-like-....--- 10. Atra (p. 18). 
~-n- eee 9. CHELONOCARPUS (p. 18). 
