206 PENTANIiRIA TRIGYNIA 



common petiole 1 to 2 feet lone, very villusc. Flowers yellowish green, in thyr * 

 panicles terminating the young branches, dioicous by abortion. Sterile flow •' 

 larger ami rather open panicles. Ovary abortive. Fertile flowers in smaller dan ° 

 thyrsoid panicles. Stamens 0? Ovary densely clothed with a long greyish" 30 

 taentose pubescence/which on ihofruit becomes a bright purplo ; jwduncles don 

 ly viliosc. -e " 



Hub. Bank of the Schuylkill ; Black Rock : not common. Fl. June. Fr. Sept -0 



Obs. This species was observed in Willistown, by Mr. Josuxsx Hoopes ; but it 

 is very rare, except along the Schuylkill. It often attains a much larger size tha 1 

 any of our other species; and the fino purple clusters;of fruit render the fertt 

 plant quite an ornamental shrub, ' e 



* * Branches smooth. 



m 



2. R. olabiia, L. Young branches and petioles glabrous ; leaflets i 

 many pairs, lance-oblong, acuminate, serrate, smooth on both sides* 

 panicles dense, terminal, Beck $ Mot. p. 75. ' 



Glabrous Rhus. Vulgo— Common Sumach. Smooth Sumaoh. 



Very lactescent. Stem 3 to 8 or 10 feet high, irregularly branching- youn* 

 branches stout and thick, with a large pith, somewhat angular and very smooth 

 Leaves pinnate ; leaflets in 10 to 12 or 15 pairs with a terminal odd one , 2 to 3 or 4 

 inches long, and half an inch to an inch wide, glabrous, green above, glaucous be- 

 neath, irregularly and sometimes obsoletely serrate, all rather obtuse at base, and 

 all sessile except the terminal one,-which is also often sessile, with a smaller 

 leaflet at its base ; common petiole 9 U) 18 inches long, glabrous, often dark purple 

 Flowers yellowisft green, in thyrsoid panicles terminating the young branches di' 

 oicous by abortion. SterileJloxceTs in larger and rather open panicles, or com- 

 pound thyrsoid racemes. Calyx-segments lanceolate, acute. Stigmas clavate 

 subsessile. Ovary abortive, In a fleshy peltate crenate-dentaie disk, in the bottom 

 of the calyx. Fertile Jloicers in smaller and more dense panicles. Stamens 

 Stigmas subsessile. Ovary clothed with a short greyish silky villus, which on thf 

 fruit becomes a bright purple, and, under a lens, is translucent, or chrystalline in 

 appearan.ce,-containing a sprightly acid ; peduncles pubescent. 

 Hah. Sterile old fields ; fence-rows, & thickets : common. Fl, Juno. Fr. Sept. Oct. 



Obs. This shrub is apt to be abundant in neglected old fields,— and its preva- 

 lence, in arable lands, is strong evidence of a poor thriftless farmer. The branches 

 and leaves are used in tanning morocco leather. The acid, in the chrystalline pu- 

 bescence of the fruit, is pronounced by Mr. Cozzens(See Ann. N. Y.Lyceum, Vol. 

 I. p. 42-3,) to be the malic,— which, he says, may be obtained pure, with very little 

 trouble, and used for some of the purposes of the citric acid. 



3. R. copalliha, L. Young: branches and petioles downy-pubescent; 

 leaflets in 4 to 6 or 7 pairs, Oblong or oval-lanceolate, mostly entire, pi- 

 lose beneath ; common petiole winged ; panicles dense, terminal. Beck 

 Bot.p. 75. ' 



Copal Rhus. Vulgd— Mountain Sumach. 



StemZlo 6 or 8 feet high, branching ; young branches rather slender, terete, pu- 

 beruient, somewhat verrucose. Leaves pinnate ; leaflets in 3 to 7rpairs (mostly 4 

 or 5 pairs) with a terminal odd one, I to 3 inches long, and half an inch to an inch 

 or inch and a quarter wide, subcoriaceous, varying from lanco-ovat* to oval and 

 •HeBS-luctolau, acuta or somtwhat acuminaU, sometimes obtuse andemargi' 



