Crataegus L.
(D.R.G., W.R.S.)
Deciduous shrubs or small trees, usually armed with spines; stems erect to spreading, sometimes with well developed trunk; young stems glabrous or pilose. Lvs either distributed along stems or in fascicles, simple, lobed to pinnatifid with margins serrate or entire, usually petiolate; lvs of non-flowering first-year shoots usually larger and broader at base than those of flowering shoots; stipules larger, persistent and somewhat leafy on long vegetative shoots, smaller and deciduous on older and shorter shoots. Infl. usually a flattened or rounded corymb of many small but showy fls terminating a leafy short shoot, rarely fls 1-3 in fascicles. Fls 5-merous, ⚥, pedicellate. Hypanthium tubular, closed at apex. Epicalyx 0. Calyx of 5 sepals; sepals short, fused at base, generally persistent, sometimes deciduous. Petals 5, often suborbicular and spreading, usually white, occasionally pink, cream or red. Stamens 5-25. Ovary semi-inferior or inferior, sunken in hypanthium; carpels 1-5, connate on inner margin at least near base; styles 1-5; ovules 2 in each locule. Fr. pome-like, usually rather small, red, yellow, blue-black or black, globose to ovoid or ovoid-ellipsoid, with ± mealy flesh and 1-5 (rarely more), woody carpels each containing 1 seed.
Probably 100-200 spp., N. temperate, concentrated on N. America. Naturalised sp. 1.
There is much uncertainty regarding the exact number of spp. which should be accepted for Crataegus; over 1000 have been described but many are apomicts which are only separable by trivial characters. Recent N. American Floras tend to place many of the earlier described taxa in synonymy. The genus is closely related to Pyracantha; some spp. have lvs superficially similar to members of this genus and also to a few Ribes spp. (Grossulariaceae). The lvs of flowering shoots are often smaller and less dissected than those of vigorous sucker shoots and first-year non-flowering shoots. In addition to the 2 hawthorns mentioned below, several other Crataegus spp. are cultivated in N.Z., particularly C. pubescens (Kunth) Steudel, Mexican thorn, with large yellow frs and its better-known hybrid C. × lavallei Hérincq, with large scarlet frs. Both are small trees.
