POLYGONATUM COMMUTATUM 9 
THE LEAF (FIG. 13, 14, 15). 
‘The upper expidermis of the leaf (Fig. 13,a; Fig. 14) is com- 
posed of elongated and flattened cells with thickened walls. ‘The 
lower epidermis (Fig. 13,1; Fig. 15) is simililar but is perforated 
by numerous stomata (Fig. 13, f). There are two palisaded cell 
layers immediately under the upper epidermis and these contain 
most of the chlorophyll (Fig. 13, b and c). Between the palisade 
cells and the lower epidermis the space is taken up by loose paren- 
cyhmatous tissue about four cells in thickness (Fig. 13, g). These 
cells have some chlorophyll and communicate with the stomata 
through the large intercellular spaces. 
; RESUME. 
The following facts are considered to be peculiarly character- 
istic of the plant :— 
1. No part of the seedling appears above ground the first 
year, but the plant simply transfers the food from the endosperm 
into its own storage parts and subsists upon it until the first leaf is 
completely developed during the second summer. 
2: Asingle green leaf is sent up in the second year and another 
in the third year, but no aérial stem is produced before the fourth 
year. 
3. When the fourth tuber of the rhizome has appeared, 
the first kas usually rotted, making it difficult to estimate the age 
of a young plant by simple inspection. 
4. A well marked vascular development of the cotyledon 
is a notable feature of the seedling anatomy. 
5. In primary roots there is a variation of the plerome 
from diarch to tetarch and in secondary roots from triarch to 
heptarch. 
6. Most of the wood bundles in the constricted portion of 
the annual growth are amphivasal while all of those in the thicker 
portion are collateral. What seems to be a probable explanation 
of this fact might be given here. The aérial stem is produced each 
year from a bud at the extremity of the rhizome, but the rhizome 
later continues growth beyond this point leaving the aérial stem 
in the position of a branch. The first part of this annual growth 
of the rhizome is a much thickened food storage organ, and since 
at this time it is not the in main line of water condition there is 
little use for xylem and the bundles there remain collateral. The 
continuations of these bundles in the later and more constricted 
