HYDROCHARITACEAE (FROG's BIT FAMILY) 85 



ping the leaves^ with verticils of 2 or 3 orders ; 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 furrotced 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 xi. 

 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 Fajiily) 



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-S-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 elougated, submerged, leafy. Spathes small, sessile. 



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



3. Limnobium. Stem very short. Leaves crowded ; blades 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 eXibd-qs, 

 marshy.) 



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

 serrulate ; stamens V) 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, 



