WATER PLANTAIN FAMILY. Allsmaceae 



broad obtuse leaves. S. latifolia, typical form, flowers 

 of the second or imperfectly the third order, and varying 

 broad or narrow, acute leaves. Form d, flowers of the 

 second order, and narrow leaves with divergent lobes, 

 common in mountain districts. Form e, flowers of the 

 second order, and lance-shaped or broader leaves, variably 

 arrowlike. The typical S. latifolia is smooth throughout, 

 with an erect flower-stalk carrying the three-petaled 

 white flowers in circles of three, the lowest one (some- 

 times more) pistillate ; the leaves nearly always arrow- 

 shaped. The seed, or achene is obovate with the beak 

 at right angles. 4-40 inches high. In sluggish or quiet 

 water of streams, and on the margins of ponds, etc. 

 Common. The var. pubescens is a distinct fine-hairy or 

 woolly form with very broad, blunt leaves. N. J. and 

 Pa. to N. C. The pollen of the arrowhead is distributed 

 by a variety of agents, not least of which are the 

 insects which frequent wet places, among them the 

 beautiful glassy-winged dragon-fly. The tendency of 

 some of the types to develop only staminate flowers 

 on one plant and pistillate on another, suggests the 

 probability that Sagittaria is beginning to rely upon 

 insects for fertilization. See Appendix. 



A tall species with a stout flower-stalk 

 Lonjr=beaked 



Arrowhead a TOSi( * sagittate, obtuse leaves. Flow- 

 Sagittaria ers of the second order above described, 



longirostra the 2-4 lower circles pistillate, with flower- 



July-Septem- stems less than J inch long. The obovate 

 seed or achene with a long, nearly erect 

 beak. 1 2| feet high. In swamps, and on the margins 

 of ponds and cold springs. Conn., N. J., and Pa. to Ky. 

 and Ala. 



Sagiitaria ^ s l en der species with small and ex- 



Engelmanniana tremely narrow sagittate leaves the lobes 

 August- of which are scarcely more than J inch 



September wide and not more than i the i engt h o f t h e 



blade. The flower-stalk about as long as the leaves, the 

 flowers of the second order, not more than an inch broad. 

 The narrow achene with a rather stout erect or backward 

 curved beak. 8-20 inches high. In shallow water of 

 ponds. N. H. and Mass, to Del., near the coast. 



