MONOCOTYLEDONS. 17 



15-20 in a single whorl; base of the short style persistent, forming 

 a beak at the inner angle of the achene ; achenes obliquely obovate, 

 2-3-keeled on the back. June-September. Common in ponds and 

 muddy places. 



II. SAGITTARIA. 



Perennial; rootstocks mostly nodose or tnber-bearing; 

 scapes erect or decumbent; leaves long-petioled, sheathing at 

 the base, the blade nerved and reticulated or wanting ; liovvers 

 monoecious or dioecious, racemed in 3-bracted whorls of 3's, 

 the upper flowers usually staminate; sepals 3, persistent; 

 petals 3, withering-persistent or deciduous ; stamens few or 

 many ; ovaries in globose heads, 1-ovuled ; style short, per- 

 sistent ; fruit a subglobose head of flattened achenes. 



1. S. LATiFOLiA Willd. Broad-leaved Arkowhead. Leaves 

 very variable in size and shape, from broadly sagittate to linear; 

 those growing on the drier soil being usually the broader ; petioles 

 6-.30 in. long, scape smooth or slightly pubescent, 6-36 in. high; 

 bracts acute ; flowers niona^cious or sometimes dioecious, white, 1 in. 

 or more in width ; pedicels of the staminate flowers twice the length 

 of those of the fertile flowers; filaments long, smooth, and slender; 

 achenes compressed, obovate, winged ; beak nearly horizontal, rhme- 

 September. Ditches and muddy places. 



2. S. GRAMixEA ]VIichx. (iRASs-LEAVED Sagittaria. Leaves 

 long-petioled, lanceolate, or elliptical, and acute at each end, 3-5- 

 nerved, or often linear, tlie earlier often reduced to phyllodia; scape 

 slender, usually longer than the leaves, simple, weak, often prostrate 

 in fruit ; bracts small, ovate, connate at the base ; flowers monfecious 

 or diiecious, on long, filiform pedicels, about ,\ in. wide; stamens 

 10-20, filaments pubescent, achenes obovate, wing-keeled, nearly 

 beakless. May-October. In ditches and sliallow pools. 



4. GRAMINE^. (HIASS FAMILY. 



Annual or perennial iierbs, sometimes slender trees ; stems 

 rounded, often groovi'd on one sid(\ usually hollow, closed 

 and enlarged at the nodes; leaves L'-ranked, with sheathing 

 bases which are usually split on the side opposite the blade 

 but are sonietinu's entire, the orifice of the sheatli usually 

 crowned with a scarious ring callc(| a ligiile ; intloresccnce in 



