310 SUMMER FLOWERS. 



angular or hastate, often coarsely and irregularly-toothed. 

 Waste ground and sea- shores. 



A. erecta : stem erect ; leaves lanceolate, the lower ones 

 broader and hastate. Cultivated ground. 



A. angustifolia : stem spreading or decumbent ; leaves 

 mostly lanceolate, or the upper ones linear. Waste places. 



A. littoralis : stems erect ; leaves still narrower than in 

 the last, often toothed. Sea-shores. 



A. rosea : annual ; stems procumbent, the whole plant 

 frosted with a white scaly meal ; leaves broadly triangular or 

 rhomboidal, coarsely-toothed ; fruiting perianth mealy-white, 

 thick, rhomboidal or orbicular, often warted, the segments 

 united to above the middle. Sea-coasts. PI. July to Sep- 

 tember. 



(254) Ceratophyllum. HORNWORT. 



C. demersum : aquatic ; stems floating, submersed ; leaves 

 whorled, twice or thrice forked, with subulate segments, usually 

 slightly-toothed on the edge ; flowers small, sessile, axillary, 

 without any real perianth, the males consisting of 1220 ses- 

 sile, oblong anthers, the females of a small ovary with a simple 

 style. Pools, slow streams, and shallow lakes. Fl. June, July. 



(255) Callitriche. WATER STARWORT. 



C. aquatica : aquatic ; stems slender, glabrous, floating in 

 water, or creeping and rooting in wet mud ; leaves obovate or 

 oblong, or the lower submerged ones narrow-linear, and ob- 

 tuse or notched at the top : the upper ones obovate, and spread- 

 ing in little tufts on the surface of the water, or all submerged 

 and linear; flowers minute, the males consisting of a single 

 stamen with a conspicuous filament, the females of a sessile 



