ORDER CXL. RLSTIACE.E. O^-) 



1. C. FLEx'iLis, (WilUl.) Stem slondcr, p^labrous, flubmersed, branch- 

 ing. Leaves verticillUe. in a whorl, linear, denticulate at the .-uiiiiuit. 

 F/owfrs solitary, axillary, sessile.— If. May — July. iStagiiant waters. 

 2—3 feet. 



Gknus hi.— RUP PIA. L. 4—1. 



(In honor of 11. B. Euppius, of Gottingen.) 



Flowers perfect, on a spadix, arising from the base of the 

 leaves. Stamens sessile. Stigmas 4. Ovaries 4. Perianth 

 none. -Frwi7 pedicellate, consisting of four 1-seeded drupes. 



1. R. makiti'ma, (L.) Stem floating, glabrous. Leaves filiform, with 

 inflated sheaths. Peduncles axillary, somewhat spiral, bearing 2 naked 

 green flowers. ^?i^A<?rs 4, sessile.— If. July. Salt marches. 



Genus IV.— POTAMOGE'TOX. L. 4—3. 

 (From potamos, a river, and geton, near.) 



Floioers perfect, on a spadix arising from the spathe. Peri- 

 anth 4-leaved. Anthers 4, sessile, alternating with the leaves 

 of the perianth. iY^f ^5 4, 1-seeded, sessile. 



1. P. FLu'iTANS, (L.) Stem branching, glabrous. Leaves floating, on 

 long petioles, sub-coriaceous, oval-lanceolate ; the lower ones narrow, 

 sessile, long. Flowers in axillary spikes, almost submersed. — If. May 

 — June. Stagnant waters. 2 — 6 feet. 



2. P. heterophyl'lum, (L.) Stem branching, glabrous ; upper leaves 

 opposite, lanceolate, 5-nerved, lower ones linear, sessile. Flowers 

 crowded on the spadix. — If. July — Aug. Stagnant waters. 



3. P. pauciflo'rum, (Pursli.) Stem branching, diffuse. Leaves linear, 

 sessile ; the upper verticillate, the lower alternate. Spadix 1 from 

 each whorl of leaves, bearing 4 — 10 flowers. — If. Through the sum- 

 mer. Shallow water. 



4. P. Lu'cEXs, (L.) Stem long, branched. Leaves submersed, ellij)tic 

 and elliptic-lanceolate, large, pellucid, veined. Spadix cvlindric, many- 

 flowered. Peduncle thickened above, varying in length. Fruit com- 

 pressed, obtusely angled, slightly keeled. — If. July — Aug. Carolina 

 to Canada. 



Order CXL.— RESTIA'CE.E. (Conl-rash Familij.) 



Flowers monoecious. Perianth 4-parted. Sianiens 4 — C, 

 attached to the perianth. OiKuy 2— 3-lobed, '2— 3-celled, with 

 a solitary, pendulous ovule in each cell. Fruit capsular. Her- 

 baceous plants, with stems naked, or bearing leaves. Flowers 

 in terminal heads, separated by bracts. 



Genus I.— ERIOCAU'LON. L. 8—3. 

 (From erion, wool, and cauion, a stem.) 



Floivers monoecious; sterile florets occupying tlic center of 

 the capitulum. Stamens 4—6. Perianth 4-parted, the 2 in- 



2 1 



