614 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
blades flat, while the blades of the lateral branch leaves are strongly 
convex above and hollowed beneath. The lateral branches being 
generally horizontal, the leaves usually hang in a more or less droop- 
ing or pendent position, while the leaves of the upright shoots are 
usually held out flat, or nearly so, at the ends of their long stiff peti- 
oles. The position can be changed in accommodation to the expo- 
sure, for the petioles have two pulvini, the basal rather small and 
the terminal very large. If we consider the pulvini as organs dis- 
tinct from the petiole, the difference between the two kinds of leaves 
of the patashte appears somewhat greater, in view of the fact that 
what has been looked upon as a petiole in the case of the lateral 
branch leaves is entirely of the nature of the pulvini, with nothing 
to represent the petiole proper, the structural element that inter- 
venes between the basal and apical pulvini of the leaves of the upright 
shoots. A comparison of the petioles shown in natural size in plates 
48 and 49 will make this point clear. From the difference in texture 
between the petioles and the pulvini it can be seen even from the 
photograph that the lateral branch leaves have only pulvini and not 
true petioles. While it would be overtechnical to describe the lateral 
branch leaves as sessile, instead of as having short petioles, the differ- 
ences are really greater than the descriptive language implies. 
In the case of the cacao there appears to be less in the way of 
structural differences between the petioles of the two classes of leaves. 
The petioles of the uprights are not so long and those of the lateral 
branches are not so short, and there is a definite constriction in the 
middle, between the thickened ends that represent the pulvini. 
MEASUREMENTS OF PETIOLES AND LEAF BLADES. 
The petioles on the upright shoots of the patashte attain a length 
of 34 cm., or about 134 inches. Usually the length is about 30 cm. 
The blades of such leaves are sometimes 50 cm. long by 30 cm. wide, 
or nearly 20 inches by 114, the base being broadly cordate, with a 
rather narrow sinus 5 to6cm. deep. Toward the ends of the upright 
shoots, below the whorls of lateral branches, the leaves are often 
much reduced in size and the petioles are much shorter. Usually 
these reduced upper leaves are about 30 cm. long by 20 cm. wide, with 
petioles 8 to 9 cm. long, but a leaf from just below a whorl was only 22 
em. long and 16.5 cm. wide. The petiole was 5 cm. long and the shal- 
low basal sinus only about 1 cm. deep. These reduced leaves form an 
apparent transition to the form of leaves shown on the lateral branches 
as far as size and reduction of length of petiole are concerned, but there 
is no true overlapping, for very much larger leaves on the lateral 
EXPLANATION OF PLATES 47-49,—Leaf characters of patashte. P1. 47, 5 leaves from an upright shoot, with 
long petioles, and 5 from a lateral branch with short petioles, to show the general difference in form and size 
of the blades. Pl. 48, section of upright with base and summit of petiole and lower part of blade, to show 
the pulviniand the insertion of the veins. PI. 49, portion of a lateral branch showing petioles and bases of 
3 leaves to compare with corresponding parts of upright shoot, plate 48. Pls, 48 and 49 natural size. 
