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



surround the leptome in the shape of a V. The innermost part of the central -cylinder is occupied 

 hv a thinwalled solid pith with no deposits of starch. 



In passing to the second internode (I s in fig. 2) we notice the same structure of epidermis, 

 collenchyma, cortex, endodermis and stereome as described above, but the number of mestome- 

 bundles is different, there being three concentric bands of five bundles in each of the two outer 

 ones and of four in the innermost. Of these the peripheral correspond with those observed in 

 the first internode, while those of the two inner bands, which are located in the pith, exhibit a 

 much weaker structure. The stereome is here reduced to a few cells on the hadrome-side or 

 entirely absent as in the innermost; the leptome shows the same development as in the peripheral, 

 while the vessels are much reduced in number; a large lacune, with remnants of some annular 

 vessels, forms a very conspicuous portion of the innermost mestome-bundles. All these 

 mestome-bundles are collateral. 



The third internode (I 3 in fig. 2) shows about the same structure, but the number of 

 mestome-bundles has increased now till eight in the outermost band, alternating with six in the 

 following, while there are six others near the center of the pith. Of these the innermost are 

 arranged in two parallel lines close to each other. 



These basal internodes thus show a very simple structure of epidermis, but in regard to the 

 other tissues these exhibit relatively the same development as the uppermost portion of the stem. 

 Let us examine the internode B, figured on Plate I, figure :!. The cuticle is smooth and the epider- 

 mis is rather small-celled, as in the basal portions. Rut stomata are present (tig. 21, PI. IV), and 

 these are surrounded by four cells, two parallel with the stoma and two vertical on this; the sto- 

 mata are level with epidermis and arranged in longitudinal rows. Hairs are frequent, consisting 

 of two cells with the apex obtuse, but no glandular were observed. Two layers of collenchyma 

 separate the epidermis from a chlorophyll-bearing thinwalled cortex of about five strata. The 

 (>ndodermis is very thinwalled and surrounds directly the peripheral band of sixteen collateral 

 mestome-bundles of the characteristic V-shape. but lacking the support of stereome. The pith 

 contains small deposits of starch, and we find here about rive somewhat irregular bands of smaller 

 mestome-bundles, each with one narrow annular and one wide reticulated vessel with some lep- 

 tome, but destitute of any mechanical support. 



THE LEAVES. 



The stem leaves, for instance L' in our figure 3. Plate I. have large blades and a tubular 

 sheath. 



The epidermis of the blade, viewed en face, consists of polygonal cells with straight radial 

 walls, becoming much narrower above ami below the mechanical tissue. Stomata occur on both 

 faces of the blade, but are, however, most numerous on the lower; they are projecting and are 

 surrounded by two pairs of subsidiary cells. (PI. V. fig. '24:.) The outer cell-wall of epidermis 

 (Pi. IV. rig. 22) is distinctly thickened on the dorsal face, much less so on the ventral. Epider- 

 mal projections of two kinds cover both faces, viz. small wartlike (fig. 30) and long clavate of 

 three cells in one row, which abound on the dorsal face. A large mass of hypodermal water- 

 storage-tissue occurs on the leptome-side of the midrib, but is absent from the hadrome. The 

 chlorenchyma consists of a very open pneumatic tissue on the dorsal face of the leaf-blade 

 (PI. IV, fig. 23), and of one single stratum of palisade cells on the ventral. Cells containing 

 raphides occur in both of these tissues, and arc located directly beneath epidermis: they are 

 very long (PI. V, fig. 25) when viewed in superficial sections, and are more or less parallel with 

 the veins. 



A rather poorly developed collenchymatic tissue of one or two strata is to be observed in 

 the midvein and below the larger parallel secondary veins, but there is none in the leaf-margins. 



The mestome bundles occur as about seven almost parallel veins that traverse the entire 

 length of the blade, and as numerous very short anastomoses. Of these the midrib is the 

 strongest developed (PI. V, tig. 26); there is a thinwalled completely closed parenchyma-sheath, 

 but no mestome-sheath. The leptome represents -a roundish group with sieve-tubes and com- 



