400 ROSACEAE 



salverform, or tubular. Sepals normally 5^ rarely 4 or 6-9, often subtended 

 by as many bractlets. Petals as many as the sepals or rarely wanting. 

 Stamens 1-many, most commonly 20, in three series. Gynoecium of 1- 

 many usually wholly distinct carpels. Fruit of achenes, follicles, or drupe- 

 lets. 



A. Fruit consisting of 1-5 deliiscent follicles. 



Carpels alternate with the sepals, or less in number; stipules none or deciduous. 



Carpels 1-5. if more than one more or less united below; seeds sliining, pear-shaped, 



with a bony coat; endosperm present. 1. Opulaster 



Carpels usually 5. distinct; seeds dull, linear or linear-lanceolate, with a thin coat; 



endosperm lacking. 



Stamens inserted on the margin of the h>T)anthium; flowers perfect; shrubs or 



undershrubs with simple leaves. 

 Filaments free; leaves entire or toothed. 



Carpels dehiscent on the ventral suture: shrubs with deciduous leaves. 

 -^ - ^ , . 2. Spiraea. 



Carpels dehiscent on both sutiu-es; cespitose tufted undershrubs with 



persistent leaves. 



Flowers racemose, rarely somewhat paniculate: stamens 20. 



^, „ 3. Petrophytum. 



1 lowers solitary, nearly sessile at the ends of the short branches; 

 stamens 10. 4. Kelseya. 



Filaments umted at the base; leaves twice or thrice 3-cleft. 



0. . ^ J , 5. Luetkea. 

 btamens inserted on the mside of the hypanthium; flowers dioecious; tall herbs 



witn twice or thrice compound leaves. 6. Ahtjncus 



Carpels opposite to the sepals; stipules present, persistent; leaves pinnately dissected. 



T> T?^„v^ ^ •*- *. J T.. , 7. Chamaebatiaria. 



H. /nuts consistmg of mdohiscent achenes or drupelets. 



1. Carpels not enclosed in a fleshy hj-panthium. 



a. Irmts of dry achenes. 



1. Ovules 2. one above the other; achenes usually 1-seeded and more or less 

 nattened, arranged in a single circle; shrubs with simple leaves. 



2. Ovules and seeds solitary; achenes usually turgid and. if many, spirally 



a. Seeds inserted at the distal end of the ovary, i. e., opposite the origin 



J . style, pendulous or in genera with basal styles ascending: 

 ^ radicle superior. 



Disk at the mouth of the hypanthium annular or obsolete; leaves and 



branches alternate. 

 Style articulated to the ovary; hypanthium from campanulate to 



almost flat, neither contracted at the throat nor closely 

 investing the achenes; flowers cymose or soUtary. 

 Stjle not basal. 



Style terminal or nearly so; ovules pendulous and anatropous. 

 Stamens separated from the receptacle by an open space; 



no indication of an annular thickening at the base 

 of the filaments. 



Hypanthium saucer-shaped to deeply campanulate; 



petals oblanceolate to obcordate or cuneate; 

 pistils usually more than 2. 

 Filaments dilated, petaloid. 9. Horkelia. 

 Filaments fiUform. 10. Ivesia. 



Hypanthium wheel-shaped; petals narrowlv linear; 

 pistils 2. 11. Comarella. 



Stamens inserted very near the base of the receptacle on 

 a more or less evident annular thickening. 



o^ 1 1 * 1 , 12. POTEXTILL.^. 



style lateral; o\ides ascending and amphitropous. 

 Achenes glabrous; herbs. 



Achenes numerous; stamens about 20. 

 Leaves odd-pinnate. 



Receptacle not enlarged in fruit; petals yellow, 

 obtuse or retuse; leaves interruptedly pin- 



nate. 13. Argentina. 



Receptacle somewhat enlarged in fruit, becom- 

 mg spongy; petals red. acute or acuminate; 

 leaves regularly pinnate. 



14. COMARTJM. 



Leaves trifoliolate; receptacle much enlarged and 

 usually red in fruit, pulpy; petals white or 

 pinkish. 15. FR-\garl\. 



Achenes 10-15; stamens 5; leaves trifoUolate. 



. , , . , 16. SlBBALDLi. 



Achenes hairy; shrubs; style club-shaped; leaves pinnate; 

 petals (m ours) yellow. 17. Dasiphora. 



