ROSE FAMILY 1 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 commi'inis. 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. Priinete. — Leaves simple: calyx deciduous: frtiit a 

 drupe. 



i. Prunus. — Stone smooth. 



Tribe 2. Spirece. — Calyx persistent : carpels 5 or more : fruit an 

 etcerio of follicles. 



2. Spiraea. — Sepals 4 — 5; carpels 5 — 12. 



Tribe 3. Rtibece. — Calyx persistent : carpels many : fruit an etario 

 of drupels. 



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

 carpel. 



Tribe 4. Potentillece. — Calyx persistent, with an epicalyx : carpels 

 4 or more : ovules 1 in each carpel : fruit an etario of achenes. 



3. Dryas. — Leaves simple; scape 1 -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 ; achenes 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 ; stamens many ; receptacle coni- 

 cal, becoming large and spongy, persistent. 



Tribe 5. Poterieai. — Petals 5 or absent : carpels 1—5 -.fruit 1 — 5^ 

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



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

 absent ; stamens 1 — 4 ; achenes 1 — 5. 



