PITTIER—PLANTS FROM COLOMBIA AND CENTRAL AMERICA. 455 
the lobes oblong to ovate, obtuse, 2 mm. long, at first erect, later reflexed ; 
stamen column 1.5 mm. long, thicker at the base; anthers 3, ovate, 0.3 mm. long, 
subconnate. Pistillate inflorescence and fruit not known. 
Type in the U. 8. National Herbarium, no. 679296, collected in forests along 
the Fat6 River above Nombre de Dios, Caribbean coast of Panama, in flower 
(male only), August 16, 1911, by H. Pittier (no. 4193). 
Of the two known species of Dialyanthera, D. otoba (H. B. K.) Warb. has 
leaves with only 9 to 15 primary veins, and almost wingless petioles, inflores- 
cences with alternate flower clusters, and floral pedicels hardly longer than 
the perianth; D. gordoniifolia (A. DC.) Warb. has 15 to 20 primary veins and 
narrowly winged or subalate petioles, alternate flower clusters, and pedicels 
shorter than the flowers. These characters are sufficient to show that the 
species just described, in which the leaves have from 20 to 25 primary veins 
and broadly winged petioles, the flower clusters are opposite, and the pedicels 
are several times longer than the perianth, is a very distinct type. 
Warburg refers to an unknown species of Dialyanthera from Chiriquf, 
Panama, represented by fruits in the museum at Munich, which may belong 
to this species. However, a fourth species is known from the rain forests of 
Costa Rica; it has been identified by John Donnell Smith as D. otoba, but I 
consider this determination doubtful. In the Costa Rican tree the branchlets 
are pubescent, not glabrous, the petioles are 2 cm. long or more and distinctly 
but narrowly winged; the blades are quite opaque and not pellucid-punctate, 
and acute rather than abruptly acuminate; and the inflorescences are usually 
geminate in the axils. A decision should be reserved, however, until we have 
the necessary material for comparison. 
MIMOSACEAE. 
THE SPICATE-FLOWERED SPECIES OF PITHECOLLOBIUM OF THE 
UNGUIS-CATI SECTION. 
INTRODUCTION. 
The spicate-flowered species of Pithecollobium of the Unguis-cati 
section include four groups, represented, respectively, by P. 
pachypus, P. hymenaeaefolium, P. ligustrinum, and P. oblongum. 
This last group contains forms with very short spikes, indicating a 
transition to the globose-flowered species of the same section. 
Pithecollobium pachypus is distinguished mainly by its relatively 
enormous pods, these thick and short, with the few seeds large in 
proportion. It has been collected only once, in El Salvador, and 
seems to represent a peculiar type without close relatives. 
The pods of the 12 remaining species are usually long, terete, and 
more or less curved, very rarely short but then flat; that is, they are 
of the type characteristic of the section. P. hymenaeaefolium and 
P. ligustrinum differ from P. oblongum in having a sessile ovary, 
flower spikes scattered along the branchlets, and an almost always 
exerted stamen tube. In the group of P. oblongum the ovary is 
stipitate and the spikes are borne on special axillary branchlets 
forming true panicles, and the stamen tube is always inclosed. 
53569—21——_2 
