364 The Botanical Gazette. [August, 
tains only leptome in L. monandra, hexandra and oe 
By comparing the development of the mestome bundles a a 
our species of Leersia it is readily seen that those of L. ex- 
andra (fig. 1), are the strongest, and that they form promin- 
ent ribs in connection with the heavy layers of stereome. This 
species, L. hexandra, possesses also larger groups of dase 
than any of the other species in question. In regard to ie 
arrangement of the stereome, however, there does not seem to 
be any difference between the various species of Leersia. Hl 
The mesophyll shows very near the same development ¥i 
' arrangement as we have seen in L. oryzoides. _L. nee 
is an exception, however, and the section (fig. 1), shows tha 
this tissue is separated in groups by the large colorless par- 
enchyma. igi 
The colorless parenchyma has therefore its greatest ie . 
opment in L. hexandra, where it is especially observab f 1 
the middle of the blade, besides this smaller groups of simi Ae 
but somewhat thickened, cells connect the bulliform cells fe) 
the dorsal and ventral face of the blade in this same species. 
The other species of Leersia agree with L. oryzoides in Li 
gard to development and arrangement of this form of paren 
chyma. : 
By considering now the leaf-structure of the genus ee 
the following characters may serve for the discrimination 0 
the species: 
Epidermis. 
Hairs on the inferior face outside the mes- ( L. oryzotdes. 
ODMH SUS eEs oe tens L. hexandra, vat. 
depauperata. 
Bulliform cells forming groups between all 
the mestome-bundles on both faces . L. hexandra. 
Epidermal-cells of the inferior face out- 
side the mestome-bundles very thick- 
walled with narrow lumen jUS BS! 
su dadilh 
Epidermal-cells very ae L. Virginie 
L. lenticularis. 
Epidermal-cells often perfectly smooth L. hexandra. 
Mestome-bundles. 
From one to three small bundles above 
the midrib 3 . - . L. orysoides. 
