Cotoneaster Medik.

Scientific Description

Common name. Cotoneaster. Family Rosaceae.

Habit and leaf form. Trees, or shrubs; evergreen (in Western Australia), or deciduous. Plants unarmed. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves; to 0.5–5 m high. Leptocaul. Mesophytic. Not heterophyllous. Leaves small, or medium-sized; not fasciculate; alternate; spiral; not decurrent on the stems; leathery, or membranous (rarely); not imbricate; petiolate. Petioles wingless. Leaves non-sheathing; simple; epulvinate. Leaf blades entire; flat; ovate, or obovate, or oblong, or elliptic, or rhombic, or orbicular; pinnately veined; cross-venulate; attenuate at the base, or cuneate at the base, or rounded at the base. Mature leaf blades adaxially glabrous; abaxially glabrous, or pilose, or pubescent, or woolly. Leaves with stipules. Stipules intrapetiolar; adnate to the petiole (at the base); free of one another; leafy; caducous, or persistent (slightly). Leaf blade margins entire; not prickly; revolute. Vegetative buds scaly. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present; glandular hairs absent. Unicellular hairs present. Complex hairs absent. Branched hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Plants not viviparous; homostylous. Entomophilous; via hymenoptera.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’, or solitary; not crowded at the stem bases; terminal, or axillary. Inflorescence few-flowered, or many-flowered. Flowers not in pairs subtended by a common bract; in cymes, or in corymbs. Inflorescences compound. The terminal inflorescence unit cymose. Inflorescences terminal, or axillary; pendent; with involucral bracts. Involucral bracts persistent, or deciduous. Involucral bracts prominent. The involucres non-accrescent. Flowers pedicellate, or subsessile; bracteate; ebracteolate; small; regular; 5 merous. Floral receptacle markedly hollowed. Free hypanthium present; campanulate, or obconic, or turbinate, or tubular (rarely); extending beyond ovary. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobulate. Calyx lobes markedly shorter than the tube. Calyx segments entire. Calyx erect; hairy, or glabrous; exceeded by the corolla; campanulate, or funnel-shaped, or tubular (rarely); regular; green; non-fleshy; persistent. Calyx lobes triangular, or ovate. Corolla present; 5; 1 -whorled; polypetalous; imbricate; regular; hairy abaxially (puberulous or pilose near base), or glabrous abaxially; hairy adaxially (puberulous, pubescent, pilose or tomentulose), or glabrous adaxially; plain; white, or red, or pink; deciduous. Petals ovate, or obovate, or orbicular; clawed; not hooded; not navicular. Corolla members entire. Androecium present. Androecial members definite in number. Androecium (6–)10–20(–22). Androecial members free of the perianth; all equal (or sub-equal), or markedly unequal (rarely); free of one another; 1 -whorled. Stamens (6–)10–22; attached inside the hypanthium (in mouth); remaining included, or becoming exserted (shortly); all more or less similar in shape; diplostemonous, or triplostemonous, or polystemonous; both opposite and alternating with the corolla members; inflexed in bud. Filaments not geniculate; glabrous; filiform. Anthers all alike; dorsifixed; versatile; dehiscing via longitudinal slits; tetrasporangiate. Gynoecium 2–5 carpelled. The pistil 2–5 celled. Carpels reduced in number relative to the perianth, or isomerous with the perianth. Gynoecium syncarpous; semicarpous; partly inferior, or inferior. Ovary plurilocular; 2–5 locular. Ovary summit glabrous, or hairy, the hairs not confined to radiating bands. Gynoecium stylate. Styles 2–5; free; simple; attenuate from the ovary; apical; not becoming exserted; hairless. Stigmas 2–5 (one per style); 1 - lobed; truncate (dilated). Placentation parietal. Ovules 2 per locule; funicled; ascending; collateral; non-arillate; anatropous.

Fruit and seed features. Fruit 3–10 mm long; stipitate; fleshy; yellow, or orange, or red, or black, or brown (red in Western Australia); not hairy; indehiscent; a drupe (pome). The drupes with separable pyrenes. Fruit enclosed in the fleshy hypanthium; 2–5 celled; 2–5 locular. Endocarp not ribbed. Dispersal unit the fruit. Dispersal by birds. Fruit 2–5 seeded. Seeds 1 per locule. Seed rows per locule 1. Seeds non-endospermic; compressed (shortly ellipsoid to obovoid, ovoid-globose); small. Cotyledons 2; folded (plano-convex). Testa hard (thin); smooth.

Geography, cytology, number of species. World distribution: widespread in temperate north Africa, Asia (except Japan), Central America and Europe, most abundant in south-west China. Adventive. Australian states and territories: Western Australia, or South Australia, or Queensland, or New South Wales, or Victoria, or Australian Capital Territory, or Tasmania. South-West Botanical Province. X=17; ploidy levels recorded up to 6 (tetraploids more numerous than diploids, the latter occurring in the Himalayas and parts of China). A genus of 90 species (sens. lat); 2 species in Western Australia; Cotoneaster glaucophyllus Franch., Cotoneaster pannosus Franch.

Economic uses, etc. Shrubs widely planted as ornamentals, borders, hedges and ground cover; source of sweet manna-like substance, high in dextrose, used in Iran and India.

Etymology. From the Latin cotoneus "quince" and -aster, a suffix expressing "an incomplete resemblance".