MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 255 



abrupt curve in the petiolar stalk immediately below the basal pinnae. 

 The pinnae also were capable of some development under these cir- 

 cumstances. Etiolated leaves contained some chlorophyl. 



Etiolation of Leaves of Monocotyledons with Parallel Vena- 

 tion. — In the greater number of species of this type examined, the 

 axis of the plant consisted of an underground tuber or rhizome, the 

 leaves arising from the axis and being held in a position variously 

 approximate to the vertical. A few instances came under observa- 

 tion in which the leaves were borne on aerial stems. The species 

 included in the group in question are : Alliuvi JVcapolitanuni (p. 

 37), A. vineale (p. 39), Caniassia (^^lamasia) (p. 87), Erythro- 

 niuni Hartivegi (p. 104), Heniei-ocallis (p. 113), Hyacinthus (pp. 

 116 and 117), Iris (p. 121), JVarcisstts Tazetta (p. 128), Ornithogal- 

 lum unibcllaiuni (p. 130), Sansevieria Giiincensis (p. 171), Sparaxts 

 (p. 180), Tipiilai'ia iinifolia (p. 181), Aplectruvi spicatum (p. 46), 

 Tritelia imijlora (p. 182), Ttdipa (p. 185). Many of these bore 

 leaves in darkness which attained a length, and sometimes also a 

 breadth, in excess of the normal and a superficial expansion equal 

 to, or greater than, that of normal organs. The leaves of Allium 

 and also those of ^lamasia were of a size approximately nor- 

 mal, although variously distorted from the usual stature and posi- 

 tion. The leaves of Aplectrwn and Tipularia were longer than 

 the normal, though of diminished width and the bracts at the 

 base of the inflorescence axes were unduly elongated, with the 

 width of organs grown in light. The leaves of Erythroniutn 

 showed but little alteration. The leaves of Heniet'ocallis did not 

 attain a size equal to that of the normal and those of Hyacinthus 

 were longer than the normal, being rolled and twisted, but showing 

 a width not much less than the normal when extended, an observa- 

 tion also made by Sachs, who describes etiolated leaves of Alliu^n 

 Cepa and A. JVeapolitanmn as being longer than the normal and 

 lacking the central lysigenous cavity. Iris produced etiolated leaves 

 of a length in excess of the normal. The greatest increase of etio- 

 lated leaves above the normal has been found by several observers 

 to be shown by JVarcissus, in which a length of three or four times 

 the ordinary measurements has been seen. Such organs are de- 

 scribed as slightly narrower than the normal by most observers, and 

 the lysigenous cavity in the center diminished in volume. In the 

 examples that came under my own observation however, the blades 



