ROSE FAMILY I 39 



horny or stony carpels are imbedded in a fleshy adherent calyx- 

 tube, comprising the Apple, Pear, Quince, Medlar, Rowan, and 

 Hawthorn. All the cultivated varieties of Apple are derived from 

 the wild Crab, Pyrus Mains, and the Pears from a thorny tree, 

 with a hard astringent fruit, Pyrus conwiwiis. The wood of the 

 Pear is very close-grained and is used in making T-squares. 

 The fruit of the Rowan, and some other species, yields malic 

 acid, and the leaves as much prussic acid as those of the Cherry- 

 Laurel. 



Tribe i. Prunece, — Leaves simple: calyx deciduous: fruit a 

 drupe. 



1. Prunus. — Stojie smooth. 



Tribe 2. Spirece. — Calyx persistent : carpels ^ or more : fruit an 

 etcErio of follicles. 



2. Spir.^a. — Sepals 4 — 5; carpels 5 — 12, 



Tribe 3. PUbece. — Calyx persistent : carpels many : fruit an etcerio 

 of drupels. 



3. RuBUS. — Receptacle convex, spongy ; ovules 2 in each 

 carpel. 



Tribe 4. Potefitillece. — Calyx pe?'sistent, ivith an epicalyx : carpels 

 4 or more : ovules i iii each carpel : fruit an etcerio of achenes. 



3. Drvas. — Leaves simple; scape i-flowered; styles becoming 

 feathery. 



5. Geum. — Leaves pinnate ; scape several-flowered ; styles be- 

 coming hooked awns. 



6. Fragaria. — Leaves ternate ; achenes on fleshy receptacle; 

 style not elongating. 



7. PoTENTiLLA. — Leaflets 3, 5, or many, palmate or pinnate ; 

 stamens many ; ache?tes many, on dry flat receptacle ; style not 

 elongating. 



8. SiBBALDiA. — Leaves ternate; stamens 5; achenes 5 — 10, on 

 dry concave receptacle. 



9. Comarum. — Leaves pinnate ; sta?nens many ; receptacle coni- 

 cal, becoming large and spongy, persistent. 



Tribe 5. Poteriea;. — Petals 5 or absent : carpels i — 5 \ fruit i — 5 

 achenes {i-seeded) enclosed in small dry calyx- tube. 



10. ALCHEMfLLA. — Sepals 4 or 5, with an epicalyx; petals 

 absent ; stamens i — 4 ; achejies i — 5. 



