1886.] BOTANICAL GAZETTE. 323 
small. The leaves of Dactylis and Poa pratensis are conduplicate 
when slowly dried, while those of Phleum are convolute. The 
leaves of Panicum plicatum, when dry, close in a zigzag manner 
like a fan. The object accomplished by the closing or rolling of 
the leaves is to cover one surface and assist in preventing excessive 
evaporation in dry weather. 
The examples here cited belong to various genera and tribes 
of grasses, and give a fair idea of the varied forms of bulliform 
cells, though these are by no means all the varieties that might be 
own. 
Ina similar manner let us now glance at some of our common 
species of Cyperacez, and compare them with some leaves of 
grasses, 
1. The leaf of Cyperus rotundus, var. Hydra, is narrow and 
thin, having a single deep band of bulliform cells above the 
midvein (fig. 11). The epidermal cells are rather large and nearly 
uniform in size. The bulliform cells are much like those of 
Dactylis glomerata. The epidermal cells on the upper side are 
much larger : aes 
In case of Kyllingia pumila the upper epidermis occupies 
nearly half the thickness of the leaf, the cells above the midvein 
being scarcely larger than those on either side (fig. 12). This leaf 
may be compared with Andropogon prinoides, though in the 
latter case the epidermal cells over the veins are small. 
3. The leaves of Heleocharis, so far as seen, have leaf- 
blades which are very small or rudimentary. 
4. The 
cells are rather small and can scarcely act as bulliform cells. 
The leaf much resembles that of Dactylis glomerata, but the bul- 
liform cells are not so deep. 
The blades of Scirpus validus, the great bulrush, are very 
short, almost rudimentary. The lacune are large and near the 
upper surface of the leaf. The cells of the upper epidermis, as well 
