240 ULMACEjE. [ Ulmut. 



Nut superior, 1-seeded. Name ; Kepas, iceparos, a horn, from 

 the spines of the fruit. Moncecia. Polyandria. 



1. C. demersum, Linn. Common Hornwort. Fruit armed 

 with two spines ; segments of the calyx notched at the ex- 

 tremity. Br. Fl. 1. p. 405. E. FL v. iv. p. 141. E. Bot. t. 

 947. 



In slow streams, ditches, and ponds. Pools near the bridge at Na- 

 van ; Doctor Scott. Near Killaleagh, isle of Rathlin, and Lough 

 Neagh ; Mr. Templeton. Fl. July. % . Floating. Stem long, slen- 

 der. Leaves setaceous, whorled, two or three times forked, 2-celled. 

 The foliage of this plant is often inflated and jointed, so as to look like 

 a Conferva. Hooker. 



2. C. submersum, Linn. Unarmed Hornwort. Fruit desti- 

 tute of spines; segments of the calyx acute, entire. Br. FL 1. 

 p. 405. E. Fl. v. iv. p. 142. E. Bot. t. 679. 



Lake near Ballynahinch, County of Down, 1808, in company with 

 Mr. Templeton. Fl. Sept. !{.. Scarcely different from the preceding, 

 but in the absence of spines on the fruit. 



ORD. 69. ULMACE^E. Mirb. Elm Family. 



Flowers perfect, or polygamous, often clustered. Periantli 

 free, monophyllous, campanulate, divided. Stamens definite, 

 inserted into the base of the perianth, straight in aestivation. 

 Ovary free, 2-celled: ovules solitary, pendulous; stigmas two, 

 distinct. Fruit 1 2-celled, indehiscent, membranous or dru- 

 paceous. Seed solitary, pendulous. Albumen little or none. 

 Embryo straight; cotyledons foliaceous; radicle superior. 

 Trees or shrubs of the colder or temperate parts of the northern 

 hemisphere, with scabrous, alternate, simple, deciduous leaves 

 and stipuhs. 



1. ULMUS. Linn. Elm. 



Perianth single, superior, persistent, 4 5-cleft, Capsule com- 

 pressed, winged all round, (a Samara] ; 1-seeded. Name, 

 according to Theis, from the Anglo-Saxon Elm. Ulm is, 

 however, still the German word for this tree. 



Pentandria. Digynia. 



1. U. campestris, Linn. Common English Elm. Leaves 

 rhomboid-ovate, acuminate, wedge-shaped and oblique at the 

 base, always scabrous above, doubly and irregularly serrated, 

 downy beneath, serratures incurved; branches wiry, slightly 

 corky, when young bright brown, pubescent; fruit oblong, 

 deeply cloven and naked. Lindl. Syn. p. 226. Br. FL 1. 

 p. 140. E. FL v. ii. p. 23. E. Bot. t. Ife86. 



In hedge-rows and woods, abundant, but scarcely indigenous. Fl, 



