102 ICOSANDR1A MONOGYNIA. [CI. 12. 



Class XII. ICOSANDEIA. Stamens 20, 

 or more, from the rim of the calyx. 



All the Genera belong to the Nat. Ord. Rosacea. 



Order I. MONOGYNIA. Style 1. 



250. PRtJNUS. Cal. inferior, 5-cleft. Pet. 5. Nut of the drupa 



with slightly prominent seams. 



31espilus 1. 



Order II. PENTAGYNIA. Styles 2—5. 



251. MeSPILUS. Cal superior, 5-cleft. Pet. 5. Apple with 2— 5 

 bony, single-valved capsules. Seeds 2. 



252. PyRUS. Cal. superior, 5-cleft. Pet. 5. Apple with 2—5 



membranous, 2-valved capsules. Seeds 2. 



253. SPIRAEA. Cal. inferior, 5-cleft. Pet. 5. Capsules of 2 mem- 



branous valves. Seeds numerous. 



Order III. POLYGYNIA. Styles numerous. 



254. RoSA. Cal. 5-cleft : tube finally pulpy, lined with hairs, and 



with numerous bristly seeds. 



255. RuBUS. Cal. 5-cleft. Berry superior, compound, deciduous. 



Recepl. spon°fv, permanent. 

 253. TORMENTlLLA. Cal. 8-cleft. Pet. 4. Seeds naked, beard- 

 less. Recept. dry, obsolete. 



260. DRYAS. Cal. 8- or 10-cleft. Pet. 5 or 8. Seeds each with a 



feathery tail. 

 259. GEUM. Cal. 10-cleft. Pet. 5. Seeds each with a bent hooked 

 tail. Recept. columnar. 



256. FRAGARIA. Cal. 10-cleft. Seeds naked, even, on the sur- 



face of a pulpy deciduous receptacle. 



261. CoMARUM. Cal. 10-cleft. Seeds naked, even, on the sur- 



face of a spongy, hairy, permanent receptacle. 



257. POTENTfLLA. Cal. 10-cleft. Seeds naked, rugged, beard- 



less. Recept. dry, obsolete. 

 Spiraea, 2, 3. 



ICOSANDRIA MONOGYNIA. 



250. PRTJNUS. Plum, and Cherry. 



1. P. Padus, 20. 1383. (Bird Cherry.) Flowers in cylindrical pen- 

 dulous clusters. Leaves deciduous, with two glands on the 

 under side at the base. 



