4a3. Rosaceae Jussieu (subfam. Rosoideae) tribe Colurieae Rydberg in N. L. Britton et al., N. Amer. Fl. 22: 240. 1908.
Shrubs [trees], subshrubs, or herbs, perennial; unarmed. Leaves alternate, sometimes opposite (Geum), pinnately compound or simple; stipules persistent, ± free or ± adnate to petiole; venation pinnate or palmate. Flowers: perianth and androecium perigynous; epicalyx bractlets absent or present; hypanthium funnelform, saucer- to cup-shaped, or obconic to obcampanulate; torus usually enlarged; carpels (2 or)3–250(–450), styles terminal (subterminal in Waldsteinia), distinct; ovules 1 or 2, basal, superposed. Fruits aggregated achenes; styles persistent, sometimes deciduous (Waldsteinia), elongate, ˂sometimes hooked, glabrous or hairy, rarely plumose˃.
Genera 4, species ca. 60 (4 genera, 22 species in the flora): North America, Mexico, South America, Eurasia, Africa, Pacific Islands (New Zealand), Australia.
Waldsteinia is recognized as distinct from Geum in this treatment, while D. Potter et al. (2007) included the former in the latter. Names are provided for users who would prefer to include Waldsteinia within Geum, as supported by molecular data (J. E. E. Smedmark and T. Eriksson 2002).
The base chromosome number for Colurieae is x = 7. Except for Fallugia, the genera of Colurieae are host to Phragmidium rusts. C. Kalkman (2004) stated that two ovules had been reported for Fallugia but that he observed only one, which would accord better with membership in Colurieae.
SELECTED REFERENCE Smedmark, J. E. E. and T. Eriksson. 2002. Phylogenetic relationships of Geum (Rosaceae) and relatives inferred from the nrITS and trnL-trnF regions. Syst. Bot. 27: 303–317.