170 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. X, NO. 6. 



the latter contains raphides and tannin, and the intercellular spaces are often very wide, 

 especially near the endodermis. A thinwalled endodermis with the Casparvan spots plainly 

 visible surrounds the central cylinder and borders directly on a continuous ring of stereome. 

 This stereome is rather thinwalled and incloses the peripheral mestome-strands completely; it 

 occurs also around the inner mestome-bundles, but is weakly developed. The collateral mestome- 

 bundles are arranged in four bands, which are barely concentric: the peripheral are the highest 

 developed, consisting of a large group of leptome and several vessels, two wide reticulated, one 

 annular, and a few scalariform. The inner mestome-bundles, which are located in the pith, 

 possess also a large leptome, but only one very wide reticulated vessel. A thinwalled pith 

 with large deposits of starch occupies the greater portion of the central cylinder. 



THE STEM ABOVE GROUND. 



The basal internodes show the same structure as the rhizome, but with the collenchyma much 

 more typically developed and with the stereome more thickwalled. 



By examining the upper internodes. which are completely covered with the leaf-sheaths, we 

 notice the same structure; epidermis, however, is more hairy, and besides the clavate hairs there 

 are also some that are sharply pointed. (PI. VI, fig. 35.) Stomata are frequent and show 

 variation in regard to the position of the surrounding cells. (PI. V, fig. 28, and PI. VI, tig. 33.) 

 Viewed en face the cells of epidermis are short and broad in the stomatiferous strata, but narrower 

 between these; the cell-walls are thin throughout. 



Beneath the epidermis are several isolated groups of collenchyma of very thickwalled cells 

 in five or six strata. The cortex contains chlorophyll and is developed as dense palisades between 

 the collenchymatic groups, but inside it represents a very open tissue of in transverse section 

 roundish cells. Raphides in long tubular cells are frequent in the cortex, besides large globose 

 crystals of Calcium oxalate. (PI. VI, tig. 36.) 



A thinwalled endodermis surrounds the central cylinder in which we notice the same structure 

 as in the rhizome — a continuous ring of thinwalled stereome, four bands of mestome strands, and 

 a pith. The last of these, the pith, contains no starch, but numerous crystals and raphides. 

 (PI. VII, tig. 38.) It is a rather open tissue with the intercellular spaces very wide. 



If we now examine the nodus, we find the same structure as described above in regard to 

 epidermis, collenchyma, cortex, endodermis, and stereome, but the mestome-bundles show 

 naturally a somewhat modified structure. The peripheral mestome -strands are almost orbicular, 

 when viewed in cross-sections, and the leptome is on both sides covered by several reticulated 

 vessels. The mestome-strands of the inner bands ai'e larger than the peripheral, since some 

 of these have fused together, forming bicollateral and perihadromatic strands; the pith was 

 observed to be moi'e solid than in the internode. 



The aerial shoot is actually terminated by a single Hower borne upon a slender, glabrous 

 peduncle; a lateral and much thicker peduncle proceeds from the base of the terminal, and bears 

 usually two or three flowers. The internal structure, of these two peduncles is almost identical, 

 with the exception of the arrangement and number of the mestome-strands. There are only 

 four or five peripheral strands in the terminal, while the lateral contains three almost concentric 

 hands of collateral mestome-bundles, about fifteen in all. The epidermis is thinwalled and bears 

 many pointed hairs; the cortical parenchyma, which occupies most of the cross-section, is very 

 open from the presence of wide lacunes. An endodermis surrounds the central cylinder with a 

 closed ring of stereome, the mestome-bundles, and the solid, but thinwalled pith. 



THE STEM-LEAVES. 



The green leaves are provided with a long, tubular sheath and a flat blade, held in a hori- 

 zontal position. 



The sheath is very veiny and covered with hairs on the outer face. These hairs represent 

 three kinds: Very long and sharply pointed, consisting of four cells, which are located along the 

 ventral suture and around the orifice of the sheath; some that are very short, but pointed like 





