298 ORDER XLIV. ROSACEA. 



L Flowers in spikes Sanguisorba, 9 



Flowers in umbels Primus, 2 



Flowers in racemes Ceraa-w, 4 



5. Ovaries 2—6 6 



Ovaries more than 6 9 



6. Leaves simple, undivided Spiraa, 5 



Leaves lobed or compound 7 



7. Flowers white Gillenia, 6 



F lowers yellow 8 



8. Flowers on a scape Wttldxteinia, 8 



Flowers on a peduncle ... Agrimonia, 10 



9. Flowers yello v Potentilla, 11 



Flowers not yellow 10 



10. Receptacle dry Geum, 7 



Receptacle fleshy 11 



11. Carpels inclosed by the receptacle Rosa, 14 



Carpels imbedded in the receptacle Fiagnria, 13 



Carpels pulpy Itubus, 18 



12. Thorny shrubs Crategus, 15 



Unarmed shrubs or small trees 13 



13. Flowers in racemes Amelanchier, 17 



Flowers not in racemes Pyrus, 16 



Sub-Order L— CHRYSOBALA'NEzE. 

 Calyx inferior. Petals and stamens more or less irregular. 

 Fruit a drupe. 



Genus 1.— CHRYSOBAL'ANUS. L. 11—1. 



(From the Greek chrusos, gold, and balanos, an acorn, in reference to its yellow fruit.) 



Calyx 5-cleft, persistent, campanulate, with nearly equal seg- 

 ments. Petals 5. Stamens numerous, those next the ovary 

 usually shortest and sterile ; ovary sessile ; ovules 2. Fruit a 

 drupe, with very little pulp, 1-seeded. Shrubs with flowers iu 

 terminal or axillary paniculate cymes. 



1. C. oblongifo'lius. (Mich.) Stem slender, prostrate, branching. 

 Leaves nearly sessile, oblong, or lanceolate-oblong, slightly crenulate, 

 glabrous, or tomentose beneath. Flowers small, terminal. Petals 

 nearly round. Fruit oblong, about 1 inch in length. — White. ^ . May 

 — June. Geo. and Ala. 1 — 2 feet. 



Sub-Order II.— AMYGDA'LEiE. 

 Calyx inferior. Fruit a drupe, 1-seeded. Bark yielding 

 gum. 



Genus II.— PRU'NUS. Tourn. 11—1. 

 (Ancient name of the Plum.) 



Calyx 5-parted, somewhat urceolate. Petals spreading, un- 

 guiculate. Stamens numerous. Ovary with 2 pendulous 

 ovules, glabrous. Fruit an ovate drupe, fleshy, with a com- 

 pressed nucleus, having grooved margins. Small trees and 

 6hrubs. Leaves with a convolute vernation, serrate. Flowers 

 usually appearing before the leaves. Plum. 



