MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 93 



The terminal portion of the etiolated stem showed a ring of pro- 

 toxylem with an indistinct cambium region, which shaded grad- 

 ually into the bast fibers external to it. The bast fibers were dis- 

 tinguishable chiefly by their position, the walls being but little 

 heavier than those of the cortical cells. The thick layer of cortex 

 was composed of elements, the radial diameter of which was greater 

 than that of the tangential. The epider- 

 mis was composed of elements with walls 

 but little heavier than those of the cortex. 

 One or two subepidermal layers of the lat- 

 ter were slightly thickened, however. A 

 few stomatal organs with widely open aper- 

 tures were found, which would represent 

 the beginning stage of lenticels. The cross 

 section of the lower portion of the etiolated 

 stem above the point of insertion of the 

 cotyledons showed an increase of the pith, 

 the formation of a thin wood ring, and the 

 absence of secondary tissues. The cam- Fig. 49. Partial cross-section 



, . , 111 1- • .of etiolated stem of Castanea. 



bium layer had taken on distinctness in ^^ epidermis. B, collapsing 

 places, and a layer of phellogen was visible layer in cortex, c, pheiiogen. 

 in the medio-cortex. The bast fiber cells ^' "^^"^^ ^^*^- ^' cambium, 

 showed about half the normal thickening. 



The normal stem shows an outer layer of phellogen bounded 

 internally by a cylinder of collenchymatous tissue immediately inter- 

 nal to which the cortical cells contain chlorophvl. 



A region of cortical cells shows the same indications of collapse 

 as in the etiolated stem, but the formation of a dividing layer 

 in the medio-cortex is not present in the normal stem. 



Cicuta maculata L. 



Clusters of dormant roots were brought into the dark room in the 

 first week in February, 1901, and the stems began growth within a 

 few days, reaching maturity in about four weeks. The stems devel- 

 oped four or five compressed internodes, from each of which a 

 single leaf arose. The leaves were held nearly erect and the petioles 

 were two or three times as long as the normal. The branches of the 

 petiole in the hypopodial region were only slightly and irregularly 

 developed, the laminar tissues remaining in very rudimentary form 



