22 



FOUNDATIONS OF BOTANY 



1. S. variabilis, var. latifolia, Willd. BROAD-LEAVED ARROW- 

 HEAD. 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 downy, 

 6-36 in. high; bracts acute. Flowers monoecious 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. Akenes with beak nearly horizontal. 

 Ditches and muddy places.* 



2. S. graminea, Michx. GRASS-LEAVED SAGITTARIA. Leaves 

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

 nerved, or often linear, the earlier 



often reduced to flattened petioles. 

 Scape slender, usually longer than 

 the leaves, simple, weak, often pros- 

 trate in fruit; bracts small, ovate, 

 connate at the base. Flowers monoe- 

 cious o dioecious, on long, thread- 

 like pedicels, about in. wide. 

 Stamens 10-20, filaments downy. 

 Akenes nearly beakless. In ditches 

 arid shallow pools.* 





FIG. 2. Diagram of Inflorescence 

 of a Grass. 



, sterile glumes ; P 15 a flowering glume ; 

 P 2 , a scaly bract (palea) ; e, transparent 

 scales (lodicules) at the base of the 

 flower ; B, the flower. 



FIG. 3. Fescue-grass (Festuca 

 pratensis). 



A, spikelet (compare Fig. 2) ; B, a 

 flower, the lodicules in front and 

 the palea behind ; C, a lodicule ; 

 Z), ovary. 



