152 PBNTANDRIA. MONOGYNIA. 



subgenus Ionia of Persoon there are 6 species in the 

 tropical parts of America, including' among them the 

 /. Ipecacuanha, said to produce the 7v/iite Ipecacuanha 

 of commerce, there are also two other species in India. 



The genus Viola, within its proper limits, is almost 

 equally divided betwixt Europe and the temperate 

 parts of North America; the few other species in India 

 and the tropical parts of America appear to indicate 

 more than one distinct genus; it is even probable that 

 Viola heretofore very unnaturally associated with the 

 Cisii/ will at last become the type of a natural order. 



226. CLAYTON I A. Gronovius. L, 



Calix biparted. Petals 5, Stigma trifid. Cap- 

 sule 1-reIled, 3-valvcd, 3 to 5-seeded. Seeds 

 rcniform. 



Herbaceous and somewhat succulent plants; roots most- 

 ly tuberous and perennial, rarely annual and fibrous; leaves 

 radical; scape producing a single pair of opposite leaAes, 

 the upper part racemose, many -flowered, petals emargi- 

 liate or bifid. (Germ in C. virgimca, mostly 5-seeded.) 



Species. 1. C. virg'ituca "2. spathulcejclia. (C. caroliniana? 

 Midi. C lanceolata? Pursh ) Abundant round Pittsburgh, 

 and appears to supercede C. vir^-inica as we proceed west,- 

 ward. 3. ahinoides. 4. perfoliata. 



A North American genus, with the exception of C. 

 sibirica; C. lanceolata of Pursh extends into Siberia, 

 and C perfoliata, which is annual, exists also in the isl- 

 and of Cuba within the tropic. 



227. RHAMNUS. L. {Buck-thorn.') 



Calix iirceolate, 4 or 5-cIeft. Petals 4 or 5, 

 minute, in the form of scales opposite the sta- 

 mina (fiometimes 0.) Stigma 2 to 4 -cleft. Ber- 

 ry 3 or4-seeded. (Flowers mostly polygamous 

 and dioicous.) 



Small trees or shrubs, with the lesser branches of- 

 ten terminating in spines; leaves somewhat opposite, fre- 

 quently alternate. Flowers axillary, lateral, and termi- 

 nal; peduncle one or many -flowered, flowers obscurely 

 coloured and inconspicuous. 



Species. 1. R. alnifolius. 2. carolinianus. 3. lanceolatus. 



Plentiful around Jsew-Orleans. 4. jninudjcrns, riowers 



