502 ORDER CX. TJLMACM. 



Style 1. Pistillate florets ; perianth 2— 4-cleft. Style I. Seed 

 1, inclosed by the perianth. 



1. P. Pennstlva'nica, (Muhl.) Stent simple, erect, striate, pubescent. 

 Leaves alternate, linear-lanceolate, pubescent, with opake dots. In- 

 volucre 3-leaved. Flowers in compact, axillary clusters. Perianth ob- 

 long, persistent, inclosing the seed. — 0. June. Upper districts Car. 

 and Geo. 12 — 15 inches. Pellitory. 



2. P. Flokida'na, (Nutt.) Stem decumbent, with erect branches, 

 pubescent near the summit. Leaves ovate, pubescent, dotted, some- 

 times nearly round. Flowers in axillary clusters. Leaves of the invo- 

 lucre nearly linear. — 0. May — Oct. Damp sandy soils. 12 — 18 in. 



Genus IV.— HU'MULUS. L. 20—5. 

 (From humus, fresh earth, from its choice of soil) 



Flowers dioecious. Sterile florets in loose axillary panicles ; 

 perianth 5-parted. Stamens 5. Fertile florets ; scales of the 

 ament large, persistent, concave, entire, 1 -flowered. Perianth 

 none. Styles 2. Seed 1. 



1. H. lu'pulus, (L.) Stem twining, scabrous. Leaves opposite, 3 — 5- 

 lobed, scabrous, serrate. Sterile florets paniculate, axillary, and termi- 

 nal ; fertile florets verticillate and sessile. — 2f . August. Hop- 



The anients of the fertile flowers constitute Hops ; the useful, bitter principle of 

 which resides in resinous, glandular scales, surrounding the fruit. The pure substance 

 is called Lupulin. 



Order CX.— ULMA'CE^E. (Mm Family.) 



Mowers perfect or polygamous. Perianth divided, campan- 

 ulate, inferior. Stamens definite, 5 — 8, inserted into the base 

 of the perianth. Ovary superior, 1-eelled, with solitary pendu- 

 lous ovules. Stigmas 2, distinct. Fruit 1 — 2-celled, mem- 

 branaceous or drupaceous. Seed solitary, pendulous. Trees 

 or shrubs. 



Genus I— UL'MUS. 5—2. 

 (A Saxon word, elm or ulm.) 



Flowers perfect. Perianth campanulate, 4 — 5-cleft. Sta- 

 mens 5 — 8. Styles 2. Fruit compressed, with a broad mem- 

 branaceous border. 



1. U. America'na, (Mich.) A large tree, with smooth, gracefully 

 recurved branches. Leaves alternate, lanceolate, oblique, doubly ser- 

 rate, with the serratures uncinate. Flowers 5 — 10, in a fascicle, pedi- 

 cellate. Fruit fimbriate. Sti/les 2, short. Fruit 1-seeded, surrounded 

 by a large, membranous wing. — T <> . Feb. — March. Rich soils. 40 — 

 100 feet. White Elm. 



2. U. ful'va, (Mich.) A small tree. Leaves large, oval, doubly ser- 

 rate, rough, sometimes slightly cordate, acuminate, pubescent. Flowers 



