322 PICKEREL-WEED FAMILY. 



extremely lonp: and slender scape: tube of the perianth not prolonged beyond 

 rhe l-celled ovary, with 3 obovate outer lobes (sepals) and 3 small inner 

 linear ones (petals), and no stamens. Ovules very numerous lining the walls. 

 Stigmas 3, sessile, 2-lobed. Fruit cylindrical, berry-like. 



1. LIMNOBIUM, FROG'S-BIT. (Name in Greek means living in 

 pools.) Flowers whitish, the fertile ones larger, in summer. 2/ 



L. Spoilgia. Floating free on stiil water 8. & W. ; has been found in bays 

 of Lake Ontario: rooting copiously; leaves l'-2' long, purple beneath, tumid 

 at base with spongy air-cells. 



2. ANACHARIS, WATER-WEED. (Name from the Greek means 



d<stitnt.<', ofc/Kinn.s.) Fl. summer. ^ 



A. Canadensis. Slow streams and ponds : a rather homely weed, with 

 long branching stems, beset with pairs or whorls of pellucid and veinless 

 1 -nerved minutely serrulate sessile leaves ('-!' long), varying from linear 

 to ovate-oblong, "the thread-like tube of the yellowish perianth often several 

 inches long. 



3. VALLiSNERiA, TAPE-GRASS, EEL-GRASS of fresh water. 



(Named for A. Vallisneri, im early Italian botanist.) Fl. late summer. 2/ 

 V. spiralis. In clear ponds and slow streams, with bright green and grass- 

 like linear leaves (l-2 long), delicately nerved and netted; fertile scapes 

 rising 2 -4 long, according to the depth of the water, afterwards coiling up 

 spirally and drawing the fruit under water to ripen. The leaves of this and 

 the preceding are excellent to show cyclosis. (See Structural Botany, p. 31, 

 Lessons, p. 167.) 



116. PONTEDEBIACE.S3, PICKEREL-WEED F. 



A few water plants, distinguished from the foregoing by having 

 the tubular corolla-like perianth free from the ovary, and the flow- 

 ers perfect. Represented by 



Sch611era graminea, or WATER STAR-GRASS ; a grass-like weed grow- 

 ing under water in streams, with branching stems beset with linear peliueid ses- 

 sile leaves; the flower with a slender salver-form pale yellow perianth, of six 

 narrow equal divisions raised to the surface on a very slender tube, and only 3 

 stamens. 



Heteranth&ra renif6rmis, MUD-PLANTAIN, in mud or shallow water 

 S. & W. ; with lloating round-kidney-shaped leaves on long petioles, and 3-5 

 ephemeral white il'-^'ers, from the Kheathing base or side of a petiole; their per- 

 ianth salver-form, with a slender tube, bearing nearlv equal divisions and 3 

 dissimi'ar stamens, one with a greenish, two with yellow anthers. 



H. Iim6sa, in mud S. & W. : distinguished by its oblong or lance-obli nq 

 leaves, and solitary blue llower. The only widely common plant of the faini.y 

 belongs to 



1. PONTEDERIA, PICKEREL-WEED. (For the Italian botanist 

 I'lintnln-ii.) Flowers in a terminal spike. Perianth of divi>ions irregularly 

 united below in a tube, the 3 most united forming an upper li|> of 3 lobes, the 

 others more spreading and wit'i more or le>s separate or lightly cohering 

 claws forming the lower lip, open only for a day, rolling up from the apex 

 downwards as it close* ; the >-ribhcd base thickening, turning green, and en- 

 cloxin^ (he fruit. Stamens (\. the .'{ lower in the throat, with incurved Jibi- 

 nients ; the .'S upper lower down and shorter, often imperfect. ( hary 3-ceIlcd, 

 L' e,-l!s empty, one with a hanging ovule. Fruit a 1 -celled 1 -seeded utricle. 

 < . \ P. COrdata, COMMON P. F, vervu here in shallow water; stem l-2hi^h, 



n.-tked below, above bearing a single petiolcd heart-shaped and oblong or lance- 



arro.s --haped obtuse leaf, and a spike of purplish-blue flowers; upper lobe with 



a conspicuous yellowish-green spot: 11. all summer. 2Z 



