276 



ROSACEA. 



Herbs. 

 Perennials. 



Pistils many on a convex receptacle, becoming achenes; calyx with a 

 row of bractlets alternating with the sepals. 



Receptacle fleshy; leaves 3-foliolate 7. Fragaria. 



Receptacle dry; leaves digitate or pinnate ... 8. Potentilla. 

 Pistil 1; leaves pinnate. 



Petals yellow; prickles of calyx hooked at tip . . 9. Agrimonia. 



Petals none ; prickles of calyx straight, but retrorsely barbed .... 



10. ACvENA. 



Annuals; diminutive plants, with palmately divided leaves; petals 

 none; pistil (in ours) 1, becoming an achene .... 11. Alchemilla. 

 Trees or shrubs with simple leaves and early-falling stipules; fruit a drupe. 

 —Drupes (Cherry Tribe). 



Flowers dioecious; pistils 5; drupes 1 to 4 12. Osmaronia. 



Flowers perfect; drupe solitary. 

 Leaves conduplicate in the bud ; drupe without bloom ; stone spherical. 



13. Cerastjs. 



Leaves convolute in the bud; drupe with bloom; stone compressed . . 



14. Prunus. 



B. Ovary inferior. 



Trees and shrubs with simple leaves and free stipules; fruit a pome, con- 

 sisting of a 2 to 5-celled ovary which is enclosed in and mostly adherent 

 to the fleshy calyx-tube.— Pome^: (Apple Tribe). 

 Leaves evergreen, coriaceous; flowers small, numerous in a corymbose 

 panicle; fruit bright red, the 2 carpels enclosed in the berry-like 



calyx 15. Heteromeles. 



Leaves deciduous. 

 Flowers in corymbs ; ovary 2 to 5-celled. 

 Pome drupe-like, containing 2 to 5 bony stones, either separable or 



united into one; branches bearing thorns .... 16. Crat^gus. 

 Pome containing 2 to 5 papery or cartilaginous carpels, each 2-seeded . 



17. Malus. 



Flowers in racemes, showy; ovary 5-celled, each cell in fruit becoming 

 2-celled by a partition from the back 18. Amelanchier. 



1. OPULASTER Medic. Nine Bark. 



Diffuse shrubs with reddish brown shreddy bark. Leaves simple; 

 stipules deciduous. Flowers white, in corymbs terminating lateral 

 leafy branchlets. Calyx campanulate, 5-cleft, persistent. Petals 5, 

 rounded, equal. Stamens 20 to 24. Pistils 1 to 5, mostly 3, some- 

 what united toward the base, becoming as many inflated 2 to 4-seeded 

 follicles dehiscent along both sutures. Seeds crustaceous, shining, 

 with copious endosperm. — -(Opulus, ancient Latin name of a kind of 

 maple tree, and aster, a suffix meaning wild.) 



1. O. opulifolius (L.) Kuntze var. capitatus. Three to 5 ft. 

 high or often with sucker-like stems nearly twice as long, commonly 

 forming with other shrubs and with climbers a dense tangle; leaves 

 roundish or ovate, 3-lobed and irregularly serrate, glabrous or 

 scabrous above, stellate-pubescent beneath, 1 to 2 in. long, on peti- 

 oles £ in. long or more; leaves of sterile shoots similar but larger; 

 pedicels and calyx pubescent; corymbs hemispherical, f to 1 in. 

 high; petals 1£ lines long; stamens alternately long and short; pods 

 divergent, commonly 3 to 4 lines long, splitting into 2 valves. — 

 (Neillia capitata Greene.) 



Common along streams in the hills, often gregarious on steep north 

 hillsides: Oakland Hills; Marin Co.; Napa Valley and northward; 

 apparently not occurring in the inner North Coast or Mt. Diablo 



