Families of Vascular Plants - EEB337H

Rosales - Rosaceae

107 genera/3100 spp., subcosmopolitan, temperate, especially N temperate. Trees, shrubs, and herbs. Leaves simple, compound, or dissected, usually spirally arranged. Stipules usually present (but not in Spiraeoideae), often joined to the petiole.

Flowers usually perfect, perigynous or (in Maloideae) epigynous. K (3-)5(-10), often appearing as lobes on a hypanthium; C (3-)5(-10), imbricate, often large, rarely absent. A (1, 5-)20 to many, usually in sets of 5 that develop centripetally, filaments usually free and inserted on hypanthium. Inner surface of hypanthium often nectariferous. G 1-many, in (most) Maloideae developing into a hypanthial (inferior) ovary.

Recently, data from molecular and morphological studies of Rosaceae evolution have provided new insights into evolution in this family. As a result, the "traditional" subdivision of the family into four subfamilies (Rosoideae, Spiraeoideae, Amygdaloideae, Maloideae) has been superceded by the phylogenetic one outlined below in which monophyletic groups within just three subfamilies (Rosoideae, Dryadoideae, Spiraeoideae) are recognized as supertribes, tribes, and subtribes.  

Judd et al. 2002 , pp. 292-298.

Tribal classification and Ontario genera of Rosaceae (Potter et al. 2007; non-Ontario genera in blue):

Rosa palustris - 9121 Bytes Rosoideae - Base chromosome number (x) = 7.
  Sanguisorbeae - Agrimonia, Sanguisorba; gynoecium usually with a single, simple pistil, fruit an achene.
  Potentilleae - Fragaria, Potentilla; x = 8 in Alchemilla. Gynoecium apocarpous, fruit an aggregate of achenes (achenetum).
  Rosa; fruit an aggregate of achenes (achenetum).
  Colurieae - Geum, Fallugia; fruit an aggregate of achenes (achenetum).
  Rubus; fruit an aggregate of drupelets (drupetum).
Dryas octopetala
Dryadoideae - Dryas, Purshia, Cowania, Chamaebatia
Members of this clade are characterized by having a symbiotic relationship with Nitrogen-fixing bacteria that infect their roots. Fruit an achene or achenetum, x = 9.
Spiraea salicifolia - 9752 Bytes Spiraeoideae - Fruit generally an aggregate of follicles (follicetum), x = 9 except as noted below.
  Sorbarieae - Sorbaria
Malus (apple)
Pyrodeae - This supertribe comprises genera previously assigned to subfamily Maloideae with more or less fleshy, indehiscent fruits, together with ones with dry, dehiscent fruits
  • Pyreae - Amelanchier, Aronia, Crataegus, Malus, Sorbus, and others with fleshy fruits (berries, polypyrenous drupes (subtribe Pyrinae; x = 17)
  • Vauquelinia (x = 15); Lindleya, and Kageneckia (x = 17) - Fruit an aggregate of capsules (coccetum)
  • Gillenia - Fruit an aggregate of follicles (follicetum); x = 9.
  Spiraeeae - Aruncus, Spiraea
  Kerrieae - Kerria
  Osmaronieae - Oemleria
Prunus (cherry) Amygdaleae - Prunus
  Neillieae - Physocarpus,

Note the many commercially important fruit plants in this family, e.g. Malus (apples), Prunus (almonds, apricots, cherries, peaches, plums), Rubus (blackberries, rasberries, etc.), Pyrus (pears), Cydonia (quince), Eriobotrya (loquat), Mespilus (medlar); also scents (Rosa) and cultivated, ornamental shrubs. "Temperate gardens would be very different if Rosaceae did not exist" (Mabberley 1987).

The Flora North America treatment of the Rosaceae (Vol. 9) is not yet available.

Flora North America


The Families of Flowering Plants
DELTA database in natural language

L. Watson and M. J. Dallwitz


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