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O'Kennon'S Hawthorn (Crataegus okennonii)

Description

Shrubs or trees, -usually main trunk dominant-, 3-120 dm. Stems usually 1 in larger plants, more in smaller plants, outer spreading; bark usually checked into rough, exfoliating plates, when usually dark, but freshly exposed - russet, sometimes deeply corrugated and dark gray-brown, or smooth, thin and exfoliating, when usually pale, rarely with prominent horizontal lenticels; extension (long) and short shoots present; compound thorns on trunk abundant or absent; -twigs - thorny, thorns 10-60(-100) mm, growth determinate (indeterminate in sect. Crataegus)-; glabrous or tomentose in first year. Leaves deciduous (sometimes winter-persistent in south), cauline, alternate, -scattered on extension shoots, often crowded on short shoots-, simple or deeply lobed; stipules deciduous with leaves or sometimes earlier, free, circinate or falcate, margins serrate to crenate, glandular; petiole present, -often glandular-; blade - ovate to narrowly elliptic or obovate, (1.2-)2-8(-12) cm, -wider leaves shallowly to deeply incised (rarely pinnately compound), the narrower less incised-, margins flat, serrate, -young teeth often gland-tipped-, venation pinnate, usually craspedodromous, surfaces glabrous to tomentose. Inflorescences terminal -on few-leaved annual short shoots that usually arise from a subterminal bud on a woody short shoot, rarely arise laterally direct from an extension shoot-, 1-50-flowered, panicles -domed, monopodial-, corymbose, or flowers solitary; bracts sometimes present, -leafy-; bracteoles present, -usually caducous-. Pedicels present. Flowers: perianth and androecium epigynous, 8-25 mm diam.; hypanthium - obconic, constricted at disc except for opening, 2-6 mm wide; sepals 5, spreading, triangular; petals 5, white, sometimes pale cream (ser. Montaninsulae) or pale pink (ser. Aestivales, ser. Molles), - circular, sometimes elliptic (ser. Lacrimatae) or - elliptic (ser. Apiifoliae, ser. Triflorae), -base barely clawed, margins - entire-; stamens 5-20 (30-45 in C. triflora), usually shorter than petals; torus absent; carpels 1-5, distinct, laterally touching, partially adnate to hypanthium, styles -1-5-, lateral, distinct, -adnate most of length, exsert-; ovules 2, -superposed-. Fruits pomes, yellow to red or purplish to black mature, suborbicular to ellipsoid or pyriform, 6-20(-25) mm diam. (larger in some cultivars), -flesh soft, sometimes hard-; hypanthium persistent; sepals often persistent, appressed to erect; carpels woody; styles usually persistent. Pyrenes 1-5, -dorsally grooved, sides plane or eroded, excavated, or pitted-. X = 17.

Taxonomic tree

  • Domain: Eukarya

    • Kingdom: Plantae

      • Phylum: Magnoliophyta

        • Class: Magnoliopsida

          • Order: Rosales

            • Family: Rosaceae

              • Genus: Crataegus