38 THE FLORA OF THE DAKOTA GROUP. 



The substance of the leaf was apparently thick but soft, as the surface 

 is covered by a g-ranulose matter resulting from the decomposition of the 

 epidermis and rendering the tertiary nervation totally obsolete. The petiole 

 is nearly 5"" long, the median nerve thick, and the secondaries, two jiairs, 

 simple, inequidistant, the lowest vein on the left side being basilar, thin, 

 short, cur\'ing close to the borders, the upper emerging a little abi.ve the 

 base and passing nearly straight up to the apex, while on the right side the 

 loAver secondary is supra basilar, nearly opposite to the upper one of the 

 left side, curving in ascending, anastomosing in the upper part of the leaf 

 with the upper secondary, which comes oiit from the midrib aboAC the 

 middle of the leaf and is aci-odi'ome. The leaf is regularly elliptical, 

 acuminate, and nearly 8*"" long and 3""" broad at the middle, with its short 

 acumen, which was originally constricted or pinched, split by compression. 



As indicated by its foi*m, the nervation and the long petiole, the leaf is 

 e^^dently that of a monocotyledonous plant. But for the absence of the 

 tertiaries at light angles to the midrib it -would be referred to the g-^nus 

 Alisma. Saporta' has described without figures as Alismacites lancifolius, 

 a leaf Avhich seems to be closely related to this one. It is petioled, lan- 

 ceolate, trinerved, the lateral nerves curved, tending toward the apex with 

 secondaries or nervilles transversely ramose, scarcely visible. The author 

 remarks that tlie leaf is of uncertain affinity, rejjroducing the type of many 

 species of Alisma. 



Habitat : Ellsworth County, Kansas. No. 758 of the collection of the 

 museum of the University of Kansas. Collected by E. P. West. 



Order ARACE^. 



Tribe COLOCASIOIDE^E. 



Subtribe SPATHICARPE^. 



Aris^ma cretacea, sp. IIOV. 

 PI. XLVI, Fig. 1, 



Organism apparently cylindrical in its original state, enlarged upward, 

 of membranous texture, striate lengthwise; striae parallel, close, straight, 

 rigid and distinct in the middle of the cylinder, diverging; cm-ved outside 

 and flexuous toward the borders. 



> £tade8, vol. 1, p. 75. 



