Sorbus L.
(D.R.G., W.R.S.)
Unarmed, deciduous trees or shrubs; trunk usually well-developed with branches forming a spreading crown; young stems often hairy; bark of older stems usually greyish. Lvs imparipinnate, with serrate or entire leaflets, or simple and toothed or lobed; stipules often deciduous, sometimes persistent and conspicuous on flowering shoots. Fls in large, showy, compound corymbs, or rarely panicles, terminating short shoots, usually with 2 uppermost lvs subtending outer part of infl., 5-merous, ⚥, shortly pedicellate, mostly small. Hypanthium obconic to urceolate. Epicalyx 0. Sepals short and lanceolate or triangular, connate at base, usually persistent, sometimes deciduous. Petals 5, spreading, white or rarely pink or pale yellow. Stamens 15-20. Ovary semi-inferior or inferior; carpels 2-5, partly free or fused, ± enclosed by receptacle; styles as many as carpels, free or partly fused; ovules 2 in each locule. Fr. a small or rarely large, dryish or mealy pome, usually red to orange, sometimes yellow, brownish, white or pink; carpels thin-walled and becoming cartilaginous or membranous; seeds 1-2 in each locule.
c. 80 spp., N. temperate. Naturalised sp. 1.
Vegetatively, this genus is very diverse and it has been variously divided into 2-4 subgenera, of which subgen. Sorbus, including the pinnate-leaved rowans, is the most familiar in N.Z. because S. aucuparia belongs to it. However, in colder parts of the country S. aria L., whitebeam, in subgen. Hahnia Medikus, is commonly grown. This has simple, toothed lvs with white undersurfaces.
