34  Harshberger—Water Storage and Conduction in 
branches aforementioned, which may arise from the sides, and 
after forming an elbow-shaped joint, grow up parallel with the 
main stem (Plate VIII, Fig. 3). In other cases, the branches 
have been broken off, and their rounded stumps are found 
covered with the weathered balsam which exudes. The 
smooth stem harbors a number of epiphytes, among which 
may be mentioned several species of 7i//andsia. The growth 
of the epiphytes on the stem gives a somewhat venerable 
and hoary aspect to the plants covered by them. In their 
epiphytic growth, the 77/andstas simply embrace the host by 
their holdfast roots, and an inspection shows no corrosion 
of the cork by a ferment action, such as would happen 
if the epiphytic roots derived a supply of food from Seneczo 
praecox. 
The base or collar of our plant is usually swollen or 
rounded (Plate VII, Fig. 1). The roots come off from the 
lower surface of this rounded base, and are several in number. 
The plant is surmounted by a dense crown of green leaves 
(Plate VII, Figs. 1 and 2), which appear after the commence- 
ment of the rainy season in Mexico (June to October). The 
leaves are developed from the apices of the branches only, are 
deciduous on the long terete petioles, cordate, much acuminate, 
sub-hastate, five to seven-lobed (Plate VII, Fig. 2 ). The 
lobes are very acuminate, spreading ; the lower ones deflexed. 
The texture is between membranaceous and fleshy. 
Before the rainy season begins, when the leaves appear, in 
the months of March or April, or during the dry season, the 
corymbs of yellow composite flowers occupy the apex of 
the branch and bear several elongated, partially bracteolated, 
yellow branches, thickened below the capitulum.* 
The structure of the stem is, however, what interests us 
most in this plant. It is succulent, easily cut across, and pre- 
sents in the living specimens, a very watery, firm internal 
pith, a small cylinder of wood, a wide cortex with chlorophyll, 
* CurTIs.—‘‘ Botanical Magazine,’’ 3d ser., vol. X. t. 4803. 1854. 
