192 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



noted that the first pair of leaves in the seedling in this plant are 

 truly foliar, and that these bract-like organs resemble nothing more 

 than the cataphyllary leaves of the older stem. It seems probable 

 that these bracts may be considered as the leaf-bases and they per- 

 sist only a short time, being alive only on the second internode from 

 the apex of the stem. 



Numerous lenticels i to 3 mm. in length and half of that in 

 width were to be seen, over the entire etiolated stem. 



The epidermal cells of the etiolated stem had collapsed in the 

 older portions, and were generally rectangular in surface view, being 

 two or three times as long as broad. In some instances, however, 

 the ends were acutely oblique. The phellogen underneath the 

 epidermis comprised five to seven layers, and the outer cortex seven 

 to nine layers, the latter being composed of elements heavily thickened 

 collenchymatously, and flattened radially. The inner cortex was also 

 similarly compressed, but the walls were not so heavily thickened. 

 The bast fibers were only slightly thickened. Internally to these 

 cells was found a mass of irregular thin-walled elements which 

 shaded gradually into the cambium, which in turn passed gradually 

 into the woody tissue. The vessels and tracheids showed larger 

 lumina than in the normal. The pith was composed of perforate 

 parenchyma richly loaded with starch, and it is to the exaggerated 

 growth of this tissue that the excessive thickness of etiolated stems 

 is to be ascribed. 



The root system of the etiolated seedling was somewhat sparse, 

 and the cotyledons were turgid and still contained some starch and 

 other food material. 



The normal stem of seedlings was furnished with a phellogen 

 much like that of the etiolated, but the epidermal layer showed a 

 number of outgrowths in the form of short-pointed hairs, which were 

 not seen in the etiolated. The outer cortex is thickened collenchym- 

 atously, and contained much starch and chlorophyl, while the inner 

 layer was composed of elements with much thinner walls. 



The bast fibers were heavily thickened. The formation of some 

 secondary tissue had begun on July 22, and the medullary rays 

 were diverted from the radial position as if torsions had been set up. 

 The outline of the stem was obtusely angular. The root system was 

 more profusely branched than in the etiolated example. 



A single seedling AEsculus was allowed to germinate in the con- 



