38 ANGIOSPERM^. 



Spatha 2-leayed. Pr. a dry 1-seeded terry. Stem 30°-40° high, on 

 stilt-like, spiny adventitious roots. '2 species : W. angusta, W. 

 maynensis ; eastern slope of Andes, 3500° above sea-level. 7. Arfeca. 

 Lys. pinnate. Pis. J3 ; spatha double. Fr. a 1-seeded drupe, with 

 fibrous rind ; sd. with ruminated perisperm. 2 species. A. C&techu, 

 Betel-nut P. Drupe red, as large as a hen's egg. Sd. as large as a 

 nutmeg ; cut into small bits, which are rolled up with lime in leaves of 

 Betel Pepper and chewed as tobacco. Pis. very fragrant. Warmer 

 parts of Asia. A. Dicksoni, wild in Malabar; sds. used in the same 

 way. 



Subdivision 2 — Ova. apocarpous ; reduced to 1 carpel in some 

 Kaiadaceae. Flowers rarely on a spadix. 



Pondwreed Alliance.— Fls. g or diclinous. Perianth of 3-4-6 seg- 

 ments, or 0. Stamens 1-6. Perisperm 0. Emb. often curved or 

 hooked. Aquatics; submerged or floating: 86. Naiadacese. 27. 

 Alismacese. 



Ord. 26. Naiadaceae. Pondwekds. — Herbs, ann. or perenn. Fr. a 

 berry or utricle. 1, Najas. J*?. Perianth 0. (f fl. of 1 stamen ; 

 9 fl. of 1 ovary with 2-4 stigmas. Fr. a nut. Emb. a macropod. 8 

 species, both worlds; all submerged, small; Ivs. narrow, opp., or 

 whorled. 2. Zostfera. Fls. of Najas; pollen confervoid (see Lesson 

 XXIII., 271). Lvs. ribbon-like, colored. 2 species, marine, cosmop. 

 Z. marina, Seawkack, Grass-wrack; lvs. several ft. long, Y wide. 

 Social ; shallow water, sea^coasts. 3. Ouvirandra. Sepals 2-3. Sta. 

 6. Ovaries 3-4. Scape with a 2-5-furcate spike. Ets. tuberculate, 

 lvs. submerged. 5 species. Ind.,Af. O. /ewesirdZis, Lattice-Lea^, 

 "Water- Yam. Lf. 1° long,'3' wide, latticed. Spike 2-furcate. Ehiz. 

 edible. Madagascar. Fig. 231. 4. Potamogeton. Fls. g , 4- 

 merous. Emb. variously curved. Lvs. various. Many spec, sub- 

 merged or floating. Cosmop., in ponds, canals, etc. P.perfolidtum^ 

 PoNDWEED ; fls. purple, lvs. orbicular, ovate, or lanceolate. Emb. 

 curved. Fig. 190, A. 



Ord. 27. Alismacese. Water-Plantains.— Fls. ij or diclinous; 

 parts distinct and free. Perianth segments 2-seriate ; 3 sepals, 3 

 petals ; stamens 6-qo , ovai-ies 3-oo . 1. Trigldchin, Arrow-Grass. 

 Fls. ^ , greenish, racemed. Emb. straight. Lvs. cylindric, fleshy. 

 Several spec. ; marshes, salt or fresh. N. Y. to Wis., N". 2. Alisma. 

 Pis. §, petals white, lilac, or rose-colored; small. Several spec, 

 cosmop. A. PZania^'o, Water-Plantain ; lvs. ribbed, large, jointed. 

 Compound panicle l°-2° long. Shallow water. 3. Sagittaria, Arrow- 

 head. Fls. of Alisma, but cP> (^ ? <''" C? $ ? i "with stamens and 

 ovaries oo. Lvs. various, sometimes sagittate. Fls. usually whorled 

 in 3s on a tall scape, (^ fls. at top. 15 species, trop. and temp, regions, 

 both worlds. Several in U. S. 4. Limndcharis. Fls. g . Lvs. 

 cordate, small ; petals yellow, large ; fls. proliferous. Few spec. ; pools, 

 S. Am. 5. Bvitomus. Fls. g . Petals colored. Stamens and ovaries 

 some multiple of 3. Ovules with dissepimenlal placentation. Lvs. 

 linear. The most highly differentiated of Endogens ; see Lesson X., 

 88, 91. B. umbelldtus, Flowering Eush. Lvs. 2°-3° long, some- 

 times striped. Scape 6°-7° high, bearing an umbel of rose-colored fls. 

 Handsome. Borders of brooks, ponds, lakes, Eur., Asia. Fls., Fig. 

 58; carpel, trans, sec, Fig. 179, C. 



Ord. 28. Triurideae. — AflSnities obscure. Fls. jf or J> ? ; 2- 



