This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Herbs, shrubs, or trees, with alternate (in some exotic genera opposite), simple or compound leaves, and regular perfect or rarely polygamo-dioecious flowers. Stipules commonly present, sometimes large. Calyx free from or adnate to the ovary, 5-lobed (rarely 4-9-lobed), often bracteolate. Disk adnate to the base of the calyx. Petals equal in number to the calyx-lobes, distinct, or none. Stamens usually numerous, distinct; anthers small, 2-celled. Carpels 1-∞, distinct, or adnate to the calyx. Ovary 1-celled or rarely imperfectly 2-celled; style terminal or lateral. Ovules 1, 2, or several, anatropous. Fruit various, mostly follicles or achenes; endosperm none, or rarely copious.
A family comprising about 75 genera and more than 1200 species, of wide geographic distribution.
A. Fruit of 1-5 dehiscent follicles. | ||
* Carpels alternate with the sepals; stipules deciduous or none. | ||
Carpels, if more than 1, united below; seeds with endosperm (Neillieae). | 1. | Opulaster. |
Carpels normally 5, distinct; seeds without endosperm (Spiraeeae). | ||
Flowers perfect; shrubs with simple leaves. | 2. | Spiraea. |
Flowers dioecious; tall herbs with pinnately 2-3-compound leaves. | 3. | Aruncus. |
** Carpels opposite the sepals; stipules persistent (Sorbarieae). | ||
Petals obovate or spatulate, imbricated; leaves pinnate. | 4. | Schisonotus. |
Petals strap-shaped, convolute in the bud; leaves trifoliolate. | 5. | Porteranthus. |
B. Fruit indehiscent, of achenes or drupelets. | ||
* Carpels not enclosed in the fleshy calyx-tube (hypanthium). | ||
I. Fruit of dry achenes. | ||
Ovaries 2-ovuled (Ulmarieae). | 6. | Filipendula. |
Ovaries 1-ovuled. | ||
Seed pendulous or ascending, borne in the ovary opposite to the base of the style. | ||
Style articulated with the ovary; calyx-tube from campanulate to nearly flat (Potentilleae). | ||
Style terminal or nearly so; ovule and seed pendulous. | 7. | Potentilia. |
Style lateral; ovule and seed ascending. | ||
Herbs; achenes glabrous. | ||
Achenes numerous; stamens about 20. | ||
Leaves odd-pinnate. | ||
Receptacle not enlarged in fruit; petals yellow, obtuse or refuse. | ||
8. | Argentina. | |
Receptacle somewhat enlarged in fruit, spongy; petals red, acute or acuminate. | ||
9. | Comarum. | |
Leaves 3-foliolate; receptacle much enlarged in fruit. | ||
Receptacle not pulpy; petals yellow. | 10. | Duchesnea. |
Receptacle very pulpy: petals white or pinkish. | 11. | Fragaria. |
Achenes 10-15; stamens 5; leaves 3-foliolate. | 12. | |
Shrubs; achenes hairy. | ||
Style filiform; leaves 3-foliolate. | 13. | Sibbaldiopsis. |
Style club-shaped; leaves pinnate. | 14. | Dasiphora. |
Style nearly basal; ovule and seed ascending. | ||
Stamens numerous; flowers bracteolate; leaves pinnate. | 15. | Drymocallis. |
Stamens 5; flowers ebracteolate; leaves 2-3-ternately compound. | 16. | Chamaerhodos. |
Style not articulated with the ovary; calyx-tube urn-shaped or cup-shaped, contracted at the | ||
throat or mouth. | ||
Style nearly basal; inflorescence cymose; petals none (Alchemilleae). | ||
Perennial herbs; stamens 4, alternate with the sepals. | 17. | Alchemilla. |
Small annual herbs; stamen 1, opposite a sepal, rarely 2-5. | 18. | Aphanes. |
Style terminal; inflorescence spicate, racemose or capitate (Sanguisorbeae). | ||
Calyx-tube not prickly; petals none. | ||
Stamens 2-4, not declined; pistil 1. | ||
Perennial herbs; stigma papillose; leaflets toothed. | 19. | Sanguisorba. |
Annual or biennial herbs; stigma brush-like; leaflets pectinate-pinnatifid. | ||
20. | Poteridium. | |
Stamens of staminate flowers numerous, declined; pistils 2. | 21. | Poterium. |
Calyx-tube and fruit prickly; petals present, yellow. | 22. | Agrimonia. |
Seed erect, basal. | ||
Style wholly deciduous (Colurieae). | 23. | Waldsteinia. |
Style persistent in whole or in part. | ||
Calyx-tube hemispheric to turbinate, persistent; herbs (Dryadeae). | ||
Calyx-lobes and petals 5; leaves pinnate. | ||
Styles jointed, the upper part deciduous. | 24. | Geum. |
Styles not jointed, wholly persistent, mostly plumose. | 25. | Sieversia. |
Calyx-lobes and petals 8 or 9; leaves simple; styles plumose. | 26. | Dryas. |
Calyx-tube salver-shaped, the limb deciduous; the tube persistent, investing the achene; | ||
shrubs or trees (Cercocarpeae). | 27. | Cercocarpus. |
2. Fruit of fleshy or nearly dry drupelets; ovary 2-ovuled (Rubeae). | ||
Drupelets very pulpy. | 28. | Rubus. |
Drupelets nearly dry, enclosed by the calyx. | 29. | |
** Carpels enclosed in the fleshy calyx-tube (Roseae). | 30. | Rosa. |
 
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