624 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
DESCRIPTIONS OF THE GENERA. 
THEOBROMA L. 
Theobroma L. Sp. Pl. 782. 1753. Puates 44, 45, 51, 53. 
Low, shade-tolerant trees of tropical undergrowth, the lateral branches formed in 
terminal clusters of 5, rarely 4 or 6. 
Leaves elliptic-obovate, narrowed toward the base, pinnately veined, naked on both 
surfaces, the petioles and young shoots hirsute with stiff erect bristles; leaves of 
lateral branches of the same form as those of the upright shoots, the petioles somewhat 
shorter, but the pulvini distinct at each end. 
Inflorescences reduced to minute fleshy twigs, only the terminal joints distinct and 
these shorter than the pedicels of the flowers, produced from adventitious buds on 
old wood of the main trunk or the larger branches appearing long after the leaves. 
Flowers larger than in Tribroma, the sepals and petals both conspicuous, light- 
colored, widely expanded; sepals narrow, tapering, and reflexed; petals longer than 
the sepals, strongly curved or folded in the bud, the basal hood with two strong parallel 
ribs, the limb longer than the hood and with a slender base folded down around the 
end of the hood; staminodes slender, naked, and tapering above, laterally compressed 
below, with bands of long hairs on the lateral faces; ovary rounded, covered with 
glandular pubescence like the sepals and the pedicel. 
Fruits obovate or fusiform, with a thick fleshy rind, longitudinally ridged and fur- 
rowed, the surface smooth or tuberculate. 
TRIBROMA Cook. 
Tribroma Cook, Journ. Washington Acad. Sci. 5: 288. 1915. Prates 46-50, 52, 54. 
Slender, erect trees, with strong upright shoots, each ending in a whorled cluster 
of three lateral branches. 
Leaves of upright shoots with long petioles and broadly ovate-cordate blades, 
palmately veined, naked above, clothed underneath with a very fine dense appressed 
stellate pubescence, like the surfaces of the branches and petioles; leaves of lateral 
branches broadly ovate-oblong, subsessile, the petioles very short and representing 
only the confluent pulvini. 
Inflorescences with pseudodichotomous branching, bracted at the articulations, 
forming a broad loose panicle or dichasium, produced near the ends of the lateral 
branches, above the axillary buds of the young leaves, entirely confined to the new 
growth. 
Flowers small, inconspicuous, dark-colored, dull reddish purple, the petals minute 
and the sepals only partly opened; sepals broadly triangular, inflexed; petals much 
shorter than the sepals, the basal hood with a single median rib, the limb rudimentary, 
represented by a minute oval, reflexed, nearly sessile appendage; staminodes robust, 
clavate, clothed above with short pubescence, naked below; ovary 5-angled, finely 
pubescent like the pedicels, sepals, petals, and staminodes, but none of the pubescence 
glandular. 
Fruits ellipsoid with a very hard woody shell, the surface broken by deep irregular 
lacune. 
These descriptions relate, of necessity, to the forms of cacao and 
patashte that are cultivated in eastern Guatemala, where the com- 
parison was made. It is not to be expected that all of the contrasted 
features will be shared in the same degree by all of the members of the 
genera. Some forms of cultivated cacao are less caulocarpous than 
others, and some have the inflorescence branches along the trunk 
