34 ARISAEMA TRIPHYLLUM 
cm. wide by 5 cm. long, with petioles 4-12 cm. long. These 
leaves come through the ground with all leaflets closely 
rolled, the laterals appressed to the petiole, the terminal erect 
and the whole inclosed in a long sheathing kataphyll (PLATE 
3, FIGS. 46, 52). PLATE 3, FIGS. 40-42, show the position of the 
leaflets of the second year leaf. As shown by the cross section 
diagram in PLATE 3, FIGS. 53, 54, the leaflets are incompletely con- 
volute. In the placing of the leaflets and their escape from the bud 
the seedling in its second year shows all the characteristics of the 
mature plant. TEXT FIG. I and PLATE 3, FIGS. 44-46, 52, show the 
leaves of mature plants and such changes as follow the appearance 
of a second leaf or a flower cluster. After the appearance of the 
first trifoliate leaf the only change to be noticed in the next four 
or five years is increase in size. Leaves of mature plants may 
reach an extreme width of 35 cm., with middle leaflet 25 cm. long 
and with petioles up to 45 cm. in length. 
As is well known, plants showing the same general maturity 
and even the same size and development of leaves differ in that 
some will produce but one leaf and others two. Seedlings produce 
but one leaf each season up to the time of the first inflorescence. 
After that time all gradations in development have been observed 
from plants without any suggestion of a second leaf, through those 
with rudimentary leaves inclosed in the petiole of the first leaf, 
to plants with two normal leaves almost equal in size. There 
seems to be no time limit for the appearance of the second leaves 
after the first inflorescence, and no uniformity in their size when 
first produced. 
As has been stated, the leaves of A. triphyllum are net-veined. 
The system of each leaflet consists of a mid-vein with five to ten 
strong lateral veinlets with an equal number of weaker laterals 
between them, and all joining their extremities with a continuous 
vein extending around the leaf at a distance of 3-8 mm. from the 
margin (TEXT FIG. 36). 
In minute structure, leaves from plants of different age show 
no noteworthy differences. As seen in section (TEXT FIG. 37) 
the leaf has a typical mesophyte structure. A single layer of epi- 
dermis, with the outer walls slightly cutinized, covers each sur- 
face. Next to the upper epidermis is a single layer of short 
