318 SUMMER FLOWERS. 



(269) Typha. BULL-RUSH. 



T. latifolia : aquatic ; steins erect, reed -like, 3-6 feet high ; 

 leaves long, erect, linear, sheathing at the base, flat above ; 

 flowers in a dense continuous spike, often more than a foot 

 long, the upper male portion yellow, the lower part dark 

 brown. CatVtail or Reed-mace. Margins of ponds, lakes, 

 and ditches. Fl. June, July. 



T. angustifolia, which is not quite so common, differs 

 chiefly in the interruption in the spike between the male and 

 the female flowers, for a space varying from a few lines to an 

 inch in length, and in having narrower stiffer leaves, and more 

 slender spikes. 



(270) Sparganium. BUR- RE ED. 



S. ramosum : aquatic ; leaves long, linear, sheathing at the 

 base ; stems erect, two feet high or more, with a few branches 

 at the summit, each bearing several smaller male heads, and 

 below them a few larger female heads, which are glabrous 

 with prominent stigmas. Margins of ponds, lakes, and 

 streams. Fl. July. 



S. simplex is rather smaller, with narrower leaves, the 

 flower-heads much fewer towards the top of the simple stem ; 

 and S. natans has weaker stems, long narrow floating leaves, 

 and very few flower-heads. 



(271) Lemna. DUCKWEED. 



L. trisulca : aquatic ; fronds floating, thin, oblong, minutely- 

 toothed at the top, and ending in a little stalk at the base, 

 with young ones growing at right angles from opposite sides, 

 each with a single root beneath. Ponds and still waters. Fl. 

 June, but rarely. 



