786 



THE NAIAD FAMILY. 



Fig. 945. 



in Britain. Fl. the 



green, 1 to 2 inches long, mostly oppo- 

 site, with a small, sheathing membran- 

 ous stipule embracing the stem within- 

 side. At the time of flowering there are 

 usually about 4 ovaries together, almost 

 sessile within the stipule, each with a 

 short style and a broad, disk-shaped 

 stigma, and a solitary stamen with a 

 slender filament in the same or in a 

 separate axil ; the anthers 2- or 4-celled. 

 When ripe the carpels are 1 to \\ lines 

 long, sessile or shortly stalked, some- 

 what curved and flattened, tipped by 

 the remains of the style ; the ribs on the 

 back often crenated, warted, or slightly 

 winged. 



In ponds, or lagoons of fresh or brack- 

 ish or even salt water ; dispersed over 

 a great part of the globe. Common 

 hole summer. 



IV. RUPPIA. RUPPIA. 



A single species, distinguished as a genus from Zannichellia by the 

 alternate leaves, 2 sessile anthers, and the carpels in fruit all stalked 

 and pear-shaped. 



1. Sea Ruppia. Ruppia maritima, Lirm. (Fig. 946.) 

 (Eng. Bot. t. 136. JR. rostellata, Bab. Man.) 



A slender, branched, floating plant, 

 much resembling in appearance the 

 Fennel Pondiveed. Leaves almost ca- 

 pillary, with a dilated, sheathing base. 

 Peduncles axillary, at first very short, 

 bearing 1 or 2 flowers, each consisting 

 of 2 almost sessile anthers, with 2 dis- 

 tinct cells, and 4 carpels, at first nearly 

 sessile. As the fruit ripens, the carpels 

 become little ovoid or pear-shaped ob- 

 liquely-pointed nuts, 1 to 1\ lines long, 

 raised on pedicels, varying from 2 or 3 

 lines to an inch in length, the common 

 peduncle also lengthening considerably. 



In salt-marshes, lagoons, and shallow 

 creeks and bays, dispersed over nearly 



