HYDROCHARITACEAE (FROG'S BIT' FAMILY) 85 



ping the leaves, with verticils of 2 or Borders ; rays and slender pedicels ascending 

 at an angle of about 45; sepals 10-striate, the hyaline margins whitish ; petals 

 2-4 mm. long, white, with yellowish claw ; stamens twice as long 

 as the carpels ; these furrowed along the back, not meeting at 

 the center of the disk. Shallow water and ditches, across the 

 continent. (Eurasia.) FIG. 45. 



2. A. Geyeri Torr. Scapes 2-4, the shorter overtopped by 45. A. Plant.-aq. 

 the long-petioled linear-lanceolate to elliptic leaves ; panicles Fruit x i. 

 usually less diffuse, the verticils in 1 or 2 orders ; the thickish 

 peticels strongly divergent in fruit,' sepals 10-14-striate, the margins rose-color ; 

 petals 1-2 mm. long, rose-color, with yellow basal spot ; stamens about equaling 

 the carpels ; these ridged on the back, meeting at the center of the disk. Locally 

 from N. Y. to N. Dak. and the Pacific. (Eurasia.) 



HYDROCHARITACEAE (FROG'S BIT FAMILY) 



Aquatic herbs, with dioecious or polygamous regular flowers, sessile or on 

 scape-like peduncles from a spathe, and simple or double floral envelopes, which 

 in the fertile flowers are united into a tube and coherent with the 1-3-celled 

 ovary. Stamens 3-12, distinct or monadelphous ; anthers 2-celled. Stigmas 3 

 or 6. Fruit ripening under water, indehiscent, many-seeded. 



1. Elodea. Stem elongated, submerged, leafy. Spathes small, sessile. 



2. Vallisneria. Stemless. Leaves narrow, elongated. Spathes pedunculate. 



3. Limnobium. Stein very short. Leaves crowded; Wades broad and spongy. Spathes 



pedunculate. 



1. ELODEA Michx. WATER-WEED 



Flowers polygamo-dioecious, solitary and sessile from a sessile tubular 2-cleft 

 axillary spathe. Sterile flowers small or minute, with 3 sepals barely united at 

 base, and usually 3 similar or narrower petals ; filaments short and united at 

 base, or none ; anthers 3-9, oval. Fertile flowers pistillate or apparently per- 

 fect ; limb of the perianth 6-parted ; the small lobes obovate, spreading. Ovary 

 1-celled, with 3 parietal placentae, each bearing a few orthotropous ovules ; the 

 capillary style coherent with the tube of the perianth ; stigmas 3, large, 2-lobed 

 or notched, exserted. Fruit oblong, coriaceous, few-seeded. Perennial slender 

 herbs, with pellucid veinless 1-nerved sessile whorled or opposite leaves. 

 The staminate flowers (rarely seen) commonly break off and float on the sur- 

 face, where they expand and shed their pollen around the stigmas of the fertile 

 flowers, raised to the surface by the prolonged calyx-tube. (Name from eXwdys, 

 marshy. ) 



1. E. canad6nsis Michx. Leaves varying from linear to oval-oblong, minutely 

 serrulate ; stamens 9 in the sterile flowers, 3 or 6 almost sessile anthers in the 

 fertile. (Anacharis Planch. ; Philotria Britton.) Slow streams and ponds, 

 common. July. (Nat. in Eu.) 



2. VALLISNERIA [Mich.] L. TAPE GRASS. EEL GRASS 



Flowers dioecious ; the sterile crowded in a head, inclosed in an ovate at 

 length 3-valved spathe borne on a short scape ; stamens mostly 3. Fertile 

 flowers solitary and sessile in a tubular spathe on an exceedingly lengthened 

 scape. Calyx 3-parted in the sterile flowers ; in the fertile with a linear tube 

 coherent with the 1-celled ovary, but not extended beyond it, 3-lobed (the lobes 

 obovate). Petals 3, linear, small. Stigmas 3, large, nearly sessile, 2-lobed. 

 Ovules very numerous, scattered over the walls, orthotropous. Fruit elongated, 

 cylindrical, berry-like. Long linear leaves wholly submerged or their ends 

 floating. The staminate flower-buds themselves break from their short pedicels 

 and float on the surface, were they shed their pollen around the fertile flowers, 



