502 ORDER CX. ULMACE,E. 



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

 1, inclosed by the perianth. 



1. P. Pknnsylva'nica, (Muhl.) Stem 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 tho seed. — 0. June. Upper districts Car. 

 and Geo. 12 — 15 inches. Pellitory. 



2. P. Florida'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. — %. 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 

 anient large, persistent, concave, entire, 1-flowercd. Perianth 

 none. Styles 2. Seed 1. 



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

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

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



The ements of the fertile flowers constitute Hops; the useful, hitter principle of 

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

 is called Lupulin. 



Order CX.— UIMA'CEM. (Mm Family.) 



Flowers perfect or polygamous. Perianth divided, campan- 

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

 of the perianth. Ovary superior, 1-celled, 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'MTJS. 5—2. 



(A Saxon word, elm or ulm.) • 



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

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

 branaceous border. 



1. U. Americana, (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. Styles 2, short. Fruit 1 -seeded, surrounded 

 by a large, membranous wing. — ^. Feb. — March. Rich soils. 40 — 

 100 feet. White Elm, 



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

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



