196 Rosaceae 



Herbs. 



Petals present. 



Styles terminal; ovules pendulous. 



Petals yellow. 4. POTENTILLA. 



Petals white. 7. HORKELIA. 



Styles lateral; ovules ascending. 5. ARGENTINA. 



Styles nearly basal. 6. DRYMOCALLIS 



Petals none; pistil 1. 10. ALCHEMILLA. 



Shrubs. 



Stems unarmed. 



Fruit a pdme. 2. HETEROMELES. 



Fruit an achene or follicle. 



Flowers solitary or somewhat fascicled. 8. CERCOCARPUS. 



Flowers in terminal racemes. 



Leaves alternate, toothed or lobed. 1. HOLODISCUS. 



Leaves fascicled, entire, minute. 9. ADENOSTOMA. 



Fruit a cluster of drupelets, berry-like. 3. RUBUS. 



Fruit a drupe. 12. PRUNUS. 



Stems prickly. 



Calyx not fleshy; fruit a cluster of drupelets. 3. RUBUS. 

 Calyx fleshy; enclosing the achenes. 11. ROSA. 



1. HOLODISCUS Maxim. 



Unarmed shrubs with simple toothed or lobed exstipu- 

 late deciduous leaves and terminal panicles of numerous 

 white flowers. Calyx deeply 5-cleft, nearly rotate. Petals 

 5, rounded. Stamens 20, inserted on an annular perigynous 

 disk. Pistils 5, distinct, becoming 1-seeded hairy carpels, 

 tardily dehiscent by the dorsal suture or indehiscent. 



1. H. discolor (Pursh) Maxim. Shrub, 1-2 m. high; the 

 branches short, rigid ; bark grayish brown, more or less shreddy ; 

 leaves ovate, cuneately narrowed to a short winged petiole, pin- 

 nately lobed or toothed above the middle, green and nearly gla- 

 brous above, whitish tomentose beneath ; panicles erect, branch- 

 ing; carpels hirsute. (Spirea discolor Pursh.) 



Occasional in the San Gabriel Mountains in the chaparral belt. 



2. H. discolor dumosus (Nutt.) Wats. Lower and more 

 compact; panicle smaller, unbranched. 



Mount San Antonio near the summit. 



2. HETEROMELES Roem. CHRISTMAS BERRY. 



A small evergreen tree or sometimes shrubby, with 

 simple coriaceous toothed leaves and terminal corymbose 



