ON THE MYROSPERMUM OF SONSONATE. 
135 
The most usual size is 3 inches in length, and 1J to lij inches 
wide. Their general shape is oblong or oval-oblong, in some 
cases ovate. They are rounded or very slightly tapering, notcordi- 
form at the base. Superiorly they contract abruptly into an 
emarginate point. To the naked eye the partial petioles and mid- 
ribs appear devoid of hairs ; but when examined by the microscope, 
short lymphatic hairs, having a glossy or resinous appearance, are 
distinctly visible on them ; and the partial petioles appear some- 
what rough from transverse rugae. The leaflets are elegantly 
marked by rounded and linear pellucid spots ; the lines being usu- 
ally parallel with, or in the direction of, the primary veins. To 
see the spots, the leaflet must be held up against a strong light and 
examined by a magnifier. 
The fruit is a one-celled, one-seeded, 
winged, indehiscent pod (called by some a 
samara, by others a samaroid legume.) 
The fruit-stalk is naked at the base, but is 
amply winged superiorly. The fruit, includ- 
ing the winged foot-stalk, varies in length, 
from about 2 to 4 inches ; the usual length 
is 2§ to 3J inches. At the peduncular ex- 
tremity, the fruit (or rather its winged foot- 
stalk) is rounded, or very slightly tapering, 
unequal-sided ; at the summit it is enlarged, 
tumid, and rounded,with a small point (the re- 
mains of the style) at the side. The mesocarp 
is fibrous; but immediately exterior to the 
endocarp it contains in receptacles a yellow 
oleo-resinous or balsamic juice, which, by 
age, hardens and resinifies. Ruiz, Kunth, 
Endlicher, and De Candolle, describe this 
juice as immediately surrounding the seed, 
and being between the seed and the lining 
(endocarp) of the shell : but this is a mis- 
take, it is exterior to the endocarp. The principal part of the 
balsam resides in two receptacles or vittae, one placed on either side; 
but if a transverse section of the fruit be examined by the micros- 
cope, numerous receptacles of the more or less dried balsam are 
perceived in all parts of the mesocarp. In the two larger recep- 
Cross section of the fruit 
and seed. (Magnified.) 
a a Epicarp. 
b b Mesocarp. 
c c Endoscarp. 
d d Large vittae or la- 
cunas containing balsam. 
e e Cotyledons. 
