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



very slender apex with several lateral ramifications; the length of the tuberous portion is about 

 2 centimeters, the thickness about 1 centimeter. Besides these there are, furthermore, some 

 that are filiform in their whole length. The leaves of the rhizome are membranaceous and buds 

 were observed in the axils of these. The stem above ground is the direct continuation of the 

 rhizome and all the internodes, even the basal, are stretched; it is erect and bears several leaves 

 with narrowly linear, conduplicate blades. Vegetative shoots are sometimes developed in the 

 axils of the lowest stem-leaves and there is usually only one terminal inflorescence unless the 

 lateral shoots develop further and become flower-bearing. The arrangement of the leaves is the 

 same as that described above as characteristic of the genus. 



Tradescantia Florid ana Wats. 



The Ramification of the Shoot. 



The species shows the habit of Commelina nudiflora; there is no rhizome, and the long, 

 slender stem is creeping with the lateral branches erect or ascending; the stem-leaves are sessile 

 with short sheaths and ovate blades. The lateral branches bear a short, membranaceous and 

 tubular fore-leaf at the base and it seems characteristic of this species that the lateral shoots, 

 although strictly axillary, break through the base of the sheath of the supporting leaf, thus the 

 shoot with its fore-leaf becomes perfectly free. The other leaves of the shoots show the same 

 shape as the supporting leaf, but it was frequently observed, however, that the first leaf above 

 the proph3'llon was merely developed as a sheath with a minute, rudimentary blade. In regard 

 to the diagram of the axillary shoot, we noticed exactly the same position of the leaves as 

 described under Commelina. The small inflorescence is terminal, sometimes accompanied by a 

 few lateral, developed in the axils of the uppermost leaves. The stems are rooting, one to two 

 secondary roots being developed at each node. 



The Internal Structure of the Vegetative Organs. 



the ROOTS. 



The secondary roots are very thin and ramify freely: they are very hairy and the thinwalled 

 epidermis covers a large-celled exodermis, of which the outer cellwalls are slightly thickened; 

 no foldings were observed, thus the root is not contractile. The cortex consists of three compact 

 strata of thinwalled cells, and the endodermis is moderately thickened on the inner and radial 

 walls. The pericambium is thinwalled and continuous. Six very short rays of hadrome alter- 

 nate with six broad groups of leptome. while the center is occupied by two very wide, reticulated 

 vessels. The conjunctive tissue is poorly represented and very thinwalled. 



THE STEM. 



Clavate hairs abound, and the outer cellwall of epidermis shows numerous longitudinal ridges, 

 covered by the thin and smooth cuticle. A collenchymatic tissue was observed beneath the 

 epidermis, but very poorly developed. The cortex constitutes a narrow zone of parenchyma, 

 containing chlorophyll. No stereome was observed, thus the thinwalled endodermis surrounds 

 the central-cylinder directly. Two bands of mestome-bundles traverse the stem, the peripheral 

 bordering on endodermis, while the innermost are located in the thinwalled but solid pith. 



THE STEM-LEAVES. 



Viewed en face epidermis of both faces of the blade shows the same structure, viz: Polyedric 

 cells with tin 1 walls straight and very thin. Clavate hairs abound on the dorsal face together 

 with the stomata, which possess two pairs of subsidiary cells parallel witli the stoma; two-celled, 

 sharply pointed hairs cover the margins, rendering these very scabrous. Viewed in transverse 

 sections epidermis shows large cells on both faces, and the outer wall is extended into a 

 number of minute, wartlike papillre, covered by a thin and smooth cuticle; these papillae 



