TKIPHYLLUM AND ArISAEMA DrACONTIUM 49 



a petiole only, the blade being shriveled before it expands. Mon- 

 strosities seem to be very frequent in the leaves of A. Dracontiiun, 

 for instance, the displacement of the mucronate point from the tip 

 to the middle of the under surface of the midrib or the multipli- 

 cation of these points upon the under surface. The blade is also 

 often lobed upon one side and in one instance both sides of the 

 leaf showed this peculiarity. 



The petioles of the leaves of both species are streaked with 

 red, the color being most abundant near the base. The petiole of 

 A. Dracontium is considerably shorter than A. triphylbim and the 

 fibro-vascular system is weaker on the whole although some stems 

 of ^. Dracontium and A. tripJiylluvi show scarcely any difference. 

 In the arrangement of tissue within the stem there is exact simi- 

 larity. The bundles are arranged to form an open cylinder gen- 

 erally, in A. Dracontium, three on each side of the largest bundle. 

 Those stems which attain the greatest development may have in 

 addition a bundle running through the center of this cylinder, 

 while in A. triphvUum the fibro-vascular system may include still 

 another bundle, completing the cylinder and making nine bundles 

 in all. 



The development of the buds goes on during the growth of 

 the seedling. Each rudimentary leaf arises as a hollow elevation 

 enclosing the next youngest. At the end of the season the stem- 

 bud of A. Dracontium has four bracts which enwrap the bud 

 at the center and A. tripJiyllum agrees exactly with this plan in 

 structure. All but the innermost of these enclosing bud leaves 

 remain as rudiments upon the corm protecting the bud. The 

 fourth grows large enough to protect the leaf as it pushes through 

 the soil the second year, but remains at its base as a membraneous 

 sheath. 



The second season all A. Dracontiiiui corms, like those of ^. 

 tripliyllwn, produce one trifoliolate leaf enclosed at the base by a 

 sheath which, in those cases where no plumule is produced, must 

 be regarded as the first leaf sent up by the plant. The functional 

 leaf of the second season is trifoliolate normally, but is subject to 

 great variation, such as the whole or partial fusion of two of its 

 lobes or the complete obliteration of one of them. Even when the 

 leaf is regularly trifoliolate great variations occur in the shape of 



