Voi,. II.] 



ROSE FAMILY. 



195 



5. Rubus. 



6. Dalibarda. 



7. Fragaria. 



Pistils numerous, ripening into i-2-seeded drupelets or achenes. 

 Pistils ripening into drupelets crowded on the receptacle. 

 Drupelets very pulpy. 



Drupelets nearly dry, enclosed by the calyx. 

 Pistils ripening into achenes. 

 Style deciduous. 



Receptacle very pulpy in fruit. 

 Receptacle not fleshy, even in fruit. 

 Pistils very numerous. 



Receptacle much enlarged in fruit; bractlets longer than calyx. 8. Duchesnea. 

 Receptacle little enlarged; bractlets mostly shorter than calyx. 



Petals white or yellow, obtuse or emarginate. 9. Potentilla. 



Petals purple, abruptly acuminate, much shorter than calyx. 10. Comarum. 

 Pistils only 1-12. 



Stamens 5; petals minute; arctic and alpine herb. n. Sibbaldia. 



Stamens numerous; petals conspicuous. 12. Waldsteinia. 



Style persistent on the achene, often plumose. 



Calyx-lobes and petals 5; leaves interruptedly pinnate. 13. Geum. 



Calyx-lobes and petals 8-9; leaves simple. 14. Dryas. 



Pistil solitary; achene with a long persistent plumose style; shrub. 15. Cercocarpus. 



Pistils 5-15, ripening into i-seeded capsules; filaments narrowed at base; herbs. 16. Ulmaria. 

 Pistils 1-4; fruit enclosed in the dry persistent calyx-tube; herbs. 



Calyx with 4 or 5 bractlets; petals none. 17. Alchemilla. 



Calyx not bracteolate, but bearing hooked prickles; petals 5. 18. Agrimonia. 



Calyx neither bracteolate nor prickly; petals none. 19. Sanguisorba. 



Pistils numerous, ripening into achenes enclosed by the fleshy persistent calyx-tube; shrubs with 

 pinnate leaves. 20. Rosa. 



i. OPULASTER Medic. Pfl. Anat. 2: 109. 1799. 

 [PHYSOCARPA Raf. New Fl. N. A. 3: 73. 1836.] 



Branching shrubs, with petioled simple palmately lobed leaves, and white flowers in ter- 

 minal corymbs. Calyx campanulate, 5-lobed. Petals 5, rounded, inserted in the throat of 

 the calyx. Stamens 20-40, inserted with the petals. Pistils 1-5, short-stipitate, when 5 al- 

 ternate with the calyx- lobes. Stigma terminal, capitate. Pods 1-5, inflated, in our species 

 at length dehiscent along both sutures, 2-4-seeded. Seeds ovoid or globose, crustaceous, 

 shining; endosperm copious. [Greek, a wild Opulus, or cranberry -tree.] 



Species about 5, i or perhaps 2 of eastern North America, 3 of the Rocky Mountains and Pacific 

 Coast, i in Mantchuria. 



i. Opulaster opulifolius (L,.) Kuntze. 

 Ninebark. (Fig. 1882.) 



Spiraea opulifolia L,. Sp. PI. 489. 1753. 



Neillia opulifolia Brew. & Wats. Bot. Cal. i: 171. 



1876. 

 OpnlasterofinlifoliusKuntze, Rev. Gen. PI. 949. 1891. 



A shrub 3-io high, with recurved branches, 

 glabrous twigs and foliage, the bark peeling off 

 in thin strips. Stipules caducous; leaves peti- 

 oled, ovate-orbicular, obtusely or acutely 3-lobed, 

 cordate, truncate or broadly cuneate at the base, 

 i / -2 / long, or larger on the young shoots, the 

 lobes irregularly crenate-dentate; corymbs ter- 

 minal, peduncled, nearly spherical, many-flow- 

 ered, i / -2 / broad; pedicels slender, glabrous or 

 slightly pubescent, s // -8 // long; flowers white or 

 purplish; calyx glabrous or nearly so; follicles 

 3-5, glabrous, shining, obliquely subulate-tipped, 

 twice as long as the calyx. 



River-banks and in rocky places, Quebec to 

 Georgia, west to Manitoba and Kansas. June. 



2. SPIRAEA L. Sp. PI. 489. 1753. 



Shrubs, with alternate simple pinnate or pinnatifid mainly stipulate leaves. Flowers 

 terminal or axillary, racemose, cymose, corymbose or paniculate, white or pink, perfect. 

 Calyx persistent, its tube mainly campanulate, 4~5-lobed. Petals 4-5, inserted on the calyx, 

 short-clawed. Stamens 20-60, distinct, inserted on the calyx; filaments filiform; anthers di- 

 dymous. Disk adnate to the calyx-tube. Pistils commonly 5 (rarely 1-8), superior, sessile 

 or short-stipitate, alternate with the calyx-lobes. Stigmas capitate or discoid; ovules 2-00. 

 Follicles usually 5, not inflated, dehiscent along i suture. Seeds linear, pendulous, the testa 

 dull; endosperm little or none. [Greek, twisting, the pods twisted in some species.] 



About 60 species, natives of the north temperate zone. Besides the following, about 2 others 

 occur in the western parts of North America. 



