428 CERATOPHYLLACEAE 



the calyx-lobes, bi'oadened upward, unappendaged. Stamens 10. Ovary 1-celled : styles 

 5, alternating witli the calyx-lobes. Capsule 1-celled, openingly by tooth-like valves. 

 Seeds black, the embryo curved. 



1. Agrostemma Githago L. Foliage pubescent with long appressed hairs. Stems 



erect, 2-9 dm. tall, branched, tlie branches erect or ascending: leaf-blades linear, 4-12 



cm. long, acute, sessile: pedicels 0.5-2.5 dm. long: calyx pubescent like the stem; tube 



cylindric, 1.5-2 cm. long, 10-ribbed ; lobes linear, longer than the tube, acute : petals with 



obovate blades 2 cm. long, rounded or notched at the apex, purple or magenta, paler at 



the base, indistinctly nerved, shorter than the calyx-lobes : seeds angular, 2 mm. in 



diameter, spiny-tuberculate all over. 



Ill fields, common in or about grain fields throughout North America. Naturalized from Europe. 

 Summer. Cokn Cocklk. Corn Rose. 



Order 11. RANALES. 



Herbs, shrubs or trees. Leaves normal, often of 2 forms on aquatic plants : 

 blades simple or sometimes compound. Flowers perfect, monoecious or dioe- 

 cious, variously disposed. Calyx and corolla of distinct and separate members. 

 Androecium of usually hypogynous stamens, which are mostly more numerous 

 than the sepals. Gynoecium of 1 or several, distinct or rarely more or less united, 

 carpels. Ovary superior. Fruit various. 



stamens usually numerous, the anther-sacs opening by slits. 



Land plants, except in Ceratophyllaceae and some Rancnculaceae : leaf-blades not peltate. 

 Flowers perfect or monoecious, if dioecious on neither vines nor herbs with simple leaves. 

 Plants with minute axillary monoecious flowers : anthers with 



horn-like appendages." Fam. 1. C'eratophylclaeae. 



Plants with perfect or rarely dioecious flowers : anthers not 

 with horn-like appendages. 

 Carpels 1 or more, distinct, at least at maturity. 



Sepals 3-1.5 : petals about as many : plants if shrubby not 



with pulpy fruit : endosperm even. Fam. 2. Ranunculaceae. 



Sepals."): petals 6: fruit pulpy : endosperm channeled. Fam. ;j. Anoxaceae. 

 Carpels more or less coherent or united into cone-like struc- 

 tures, or immersed in the pulpy receptacle. 

 Sepals valvate. " Fam. 3. Anoxaceae. 



Sepals imbricated. Fam. i. Maonoi.iaceae. 



Flowers dioecious : vines with simple leaves. Fam. 5. Menispermaceae. 



\\'ater plants : emersed or floating leaves with peltate blades. 

 Carpels several and distinct. 



Carpels not in a fleshy receptacle : sepals and petals 3 or 4 each : 



stamens 3-18. Fam. ti. Cabombaceae. 



Carpels immersed in a fleshy receptacle: sepals and petals nu- 

 merous: stamens indefinite. Fam. 7. Nelu.mbonaceae. 

 Carpels united into a compound pistil. Fam. S. Nymphaeaceae. 

 Stamens few and definite, the anther-sacs opening by hinged valves, 



es.cept in Podophyllum. Fam. 9. Podhphvllaceae. 



Family 1. CERATOPHYLLACEAE A. Gray. Hornwort Family. 



Aquatic perennial herbs, with submersed jointed branching stems. Leaves 

 whorled : blades 2-cleft or Hnely dissected, the filiform segments forking. 

 Flowers monoecious, inconspicuous, axillary, sessile. Calyx herbaceous. Sepals 

 6-12, narrow, rather valvate, toothed or cleft at the apex. Staminate flowers 

 with 10-24 stamens crowded on a flat or convex recei^tacle : filaments very short : 

 anthers opening by longitudinal cracks, the connective produced into an often 

 2-3-toothed fleshy appendage. Pistillate flowers without staminodia. Ovary 

 1-celled, sessile : style cylindric. Ovule solitary, anatropous, pendulous. Fruit 

 nut-like, somewhat fiattened, 1-celled, naked : i>ericarp leathery or crustaceous. 

 Seed pendulous, with a membranous testa. Endosperm wanting. Embryo 

 straight. 



CERATOPHYLLUM L. 



Characters of the family. The plants flower mainly in the summer. 



Aehenes unarmed. 1. ('. iiiihmerstini. 



Aehenes armed on the edges with spines. 



Leaves 0-9 in a whorl ; segments spiny-toothed : aehenes with a spine on either side of the base. 



2. C. dcmersiim. 



Leaves 9-12 in a whorl ; segments bristly-toothed : aehenes fringed with spines. 3. C. echinatnni. 



