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



branch. Purely vegetative .shoots are frequent; they are developed on the lateral shoots and 

 contain no rudiments of flowers. 



If we examine the ramification we notice an addorsed bicarinate foreleaf at the base of each 

 lateral branch and at the base of each axillary inflorescence. The diagram of the shoot agrees 

 very well with that of C. nudiflora, described above, but there is no stem-leaf situated directly 

 on the floral shoot; thus the foreleaf is the only loaf below the spathe. By comparing the exact 

 position of the foreleaf with that of the spathe we noticed that the latter was turned ninety 

 degrees to the side of the former, as iu Commelina rmdiflora. 



The Internal Structure of the Vegetative Organs, 

 the roots. 



As described above, the secondary roots are quite thick and densely covered with root-hairs; 

 the} 7 represent a combination of two types, since they are contractile and contain large deposits 

 of starch. Epidermis is thinwalled, and the cells are stretched radially. (PI. VII, fig. 41, Ep.) 

 There is an exodermis (Ex. in fig. 41) of one layer, with the cells stretched in the same way, and 

 of which the cell-walls show numerous foldings when examined in longitudinal radial sections. 

 About four strata of slightly thickened stereomatic tissue separate the exodermis from the 

 cortex proper. These stereomatic cells are much shorter than typical stereome, and their cross- 

 walls are horizontal instead of oblique. 



The cortex represents a broad tissue of about thirty layers, the cells of which are thinwalled 

 and round when viewed in transverse sections, and they are filled with starch. The cortical 

 parenchyma exhibits a very regular radial arrangement with rhombic intercellular spaces. 

 Numerous crystal-ducts occur in the cortex. They are very long, but much narrower than the 

 surrounding cortical cells and contain bundles of raphides. 



Endodermis is small-celled and thinwalled, with the Casparyan spots plainly visible, but 

 contains no starch. The pericambium consists of a single layer, and is continuous in some roots, 

 but interrupted by the proto-hadrome in others. The hadrome forms twelve short rays, with 

 the proto-hadrome vessels single or two or three together arranged side by side. The leptome 

 is well developed in broad groups, separated from the center by several layers of thinwalled 

 conjunctive tissue. 



The lateral roots are much more slender, and they are not contractile; otherwise the epidermis 

 and exodermis show the same structure as observed in the secondary roots. Cortex consists 

 here of only five layers, with no deposits of starch and with no crystals. Endodermis is thin- 

 walled, or the inner and radial walls may be slightly thickened. The pericambium is continuous 

 and surrounds five to six very short rays of hadrome with the proto-hadrome-vessels mostly 

 single; a very wide reticulated vessel occupies the center of the root. The leptome is well 

 developed, but the proto-leptome cells less distinct than in the thick roots. 



THE RHIZOME. 



The basal persisting internode shows the following structure: Epidermis is moderately 7 

 thickened on all the cell-walls, perfectly glabrous and covered by a smooth, thick cuticle. The 

 cortex is moderately thickwalled and consists of numerous layers filled with starch; tubular 

 raphide-eells abound here. Two almost concentric rings of mestome-strands are located in the 

 cortex; they are collateral, and each is surrounded by a sheath of cells which are distinctly 

 smaller than the surrounding cortex and contain no starch. The innermost portion of the inter- 

 node is occupied by a solid parenchyma of the same structure as the cortex and with similar 

 deposits of starch. 



THE STEM ABOVE GROUND. 



Epidermis is here thinwalled and quite hairy from small four-celled hairs with the apical 

 cell somewhat curved, thus they represent minute hooks; stomata are present with two pairs of 

 subsidiary cells very plainly differentiated. (PI. VII, fig. 40.) The cortex is thinwalled except 



