7. CRATÆGUS. Hawthorn.
Trees or shrubs, with usually dark scaly bark, rigid terete more or less zigzag branchlets marked by oblong mostly pale lenticels, and by small horizontal slightly elevated leaf-scars, light green when they first appear, becoming red or orange-brown and lustrous or gray, rarely unarmed or armed with stout or slender short or elongated axillary simple or branched spines generally similar in color to that of the branches or trunk on which they grow, often bearing while young linear elongated caducous bracts, and usually producing at their base one or rarely two buds often developing the following year into a branch, a leaf, or a cluster of flowers, or sometimes lengthening into a leafy branch. Winter-buds small, globose or subglobose, covered by numerous imbricated scales, the outer rounded and obtuse at apex, bright chestnut-brown and lustrous, the inner accrescent, green or rose color, often glandular, soon deciduous. Leaves conduplicate in the bud, simple, generally serrate, sometimes 3-nerved, often more or less lobed, especially on vigorous leading branchlets, membranaceous to coriaceous, petiolate, deciduous; stipules often glandular-serrate, linear, acuminate, frequently bright-colored, deciduous, or on vigorous branchlets often foliaceous, coarsely serrate, usually lunate and stalked and mostly persistent until autumn. Flowers pedicellate, in few or many-flowered simple or compound cymose corymbs terminal on short lateral leafy branchlets, with linear usually bright-colored often glandular caducous bracts and bractlets leaving prominent gland-like scars, the lower branches of compound corymbs usually from the axils of upper leaves; branches of the inflorescence mostly 3-flowered, the central flower opening before the others; calyx-tube usually obconic, 5-lobed, the lobes acute or acuminate and usually gland-tipped, rarely foliaceous, glandular-serrate or entire, green or reddish toward the apex, reflexed after the flowers open, persistent and often enlarged on the fruit, or deciduous; disk thin or fleshy, entire, lobed or slightly sulcate, concave or somewhat convex; petals imbricated in the bud, orbicular, entire or somewhat erose or rarely toothed at apex, white or rarely rose color, spreading, soon deciduous; stamens often variable in number in the same species by imperfect development, but normally 5 in 1 row and alternate with the petals, or 10 in 5 pairs in 1 row alternate with the petals, or 15 in 2 rows, those of the outer row in 5 pairs opposite the sepals and alternate with and rather longer than those of the inner row, or 20 in 3 rows, those of the inner row shorter and alternate with those of the 2d row, or 25 in 4 rows, those of the 4th row alternate with those of the 3d row; filaments broad at base, subulate, incurved, often persistent on the fruit; anthers pale yellow to nearly white, or pink to light or dark rose color or purple; ovary composed of 1—5 carpels inserted in the bottom of the calyx-tube and united with it; styles free, with dilated truncate stigmas, persistent on the mature carpels; ovules ascending; raphe dorsal; micropyle inferior. Fruit subglobose, ovoid or short-oblong, scarlet, orange-colored, red, yellow, blue, or black, generally open and concave at apex; flesh usually dry and mealy; nutlets 1—5; united below, more or less free and slightly spreading above the middle, thick-walled, rounded, acute, or acuminate at apex, full and rounded or narrowed at base, rounded or conspicuously ridged and grooved on the back, flattened, or nearly round when only 1, their ventral faces plane or plano-convex, in some species penetrated by longitudinal cavities or hollows, and marked by a more or less conspicuous hypostyle sometimes extending to below the middle or nearly to the base of the nutlet. Seed solitary by abortion, erect, compressed, acute, with a membranaceous light chestnut-brown coat; embryo filling the cavity of the seed; cotyledons plano-convex, radicle short, inferior.
Cratægus is most abundant in eastern North America, where it is distributed from Newfoundland to the mountains of northern Mexico, and is represented by a large number of arborescent and shrubby species. A few species occur in the Rocky Mountains and Pacific-coast regions, and in China, Japan, Siberia, central and southwestern Asia, and in Europe. The genus is still very imperfectly known in North America, and in the absence of sufficient information concerning them several arborescent species are necessarily excluded from the following enumeration. The beautiful and abundant flowers and showy fruits make many of the species desirable ornaments of parks and gardens, and several are cultivated. Of exotic species, the Old World Cratægus Oxyacantha L., and C. monogyna Jacq., early introduced into the United States as hedge plants, have now become naturalized in many places in the northeastern and middle states. Cratægus produces heavy hard tough close-grained red-brown heartwood and thick lighter colored usually pale sapwood; useful for the handles of tools, mallets, and other small articles.
The number of the stamens, although it differs on the same species within certain usually constant limits, and the color of the anthers, which appears to be specifically constant with one exception, afford the most satisfactory characters for distinguishing the species in the different groups.
Cratægus, from κράτος, is in reference to the strength of the wood of these trees.
CONSPECTUS OF THE NATURAL GROUPS OF THE NORTH AMERICAN ARBORESCENT SPECIES.
1. Nutlets without ventral cavities. *Veins of the leaves extending to the points of the lobes only. †Petioles short, usually slightly wing-margined above the middle, glandless or with occasional minute glands; leaves cuneate at base. Corymbs compound, generally many-flowered; flowers appearing after the unfolding of the leaves; flesh of the fruit usually green or greenish yellow, dry and mealy. Leaves coriaceous or subcoriaceous, rarely thin, dark green and shining above, usually serrate only above the middle, their veins thin except on vigorous shoots; fruit mostly subglobose to short-oblong; nutlets 1—5, thick, usually obtuse and rounded at the ends, prominently ridged on the back.I. Crus-galli ([page 400]). Leaves membranaceous or subcoriaceous, mostly acute, their veins prominent; fruit short-oblong to subglobose, often conspicuously punctate, ⅓′—1′ long; nutlets 2—5, prominently ridged on the back.II. Punctatæ ([page 422]). Corymbs simple, few-flowered; flowers appearing with or before the unfolding of the leaves; fruit scarlet, lustrous; flesh yellow, juicy, subacid; nutlets rounded and slightly grooved on the back.III. Æstivales ([page 434]). †Petioles elongated, slender, eglandular or occasionally glandular; corymbs many-flowered (few-flowered in one species each of Dilatatæ and Intricatæ). ++Leaves acute or acuminate at the ends, broad at base on one species; fruit not more than ⅝′ in diameter; flesh usually thin and dry.IV. Virides ([page 437]). ++Leaves usually broad at base. Fruit subglobose to short-oblong, often broader than high, red or green, often slightly 5-angled, pruinose; mature calyx raised on a short tube; flesh of the fruit dry and mealy; nutlets 5, grooved on the back.V. Pruinosæ ([page 449]). Fruit subglobose to short-oblong, ovoid or obovoid, generally longer than broad, rarely slightly pruinose, mature calyx sessile; flesh of the fruit dry and mealy; stamens 10, anthers rose color; leaves hairy above early in the season.VI. Silvicolæ ([page 453]). Fruit short-oblong to obovoid, red or scarlet; flesh of the fruit usually soft and juicy; anthers rose color or pink; leaves thin, at maturity glabrous below.VII. Tenuifoliæ ([page 456]). Fruit subglobose, oblong or obovoid, crimson, scarlet, or rarely yellow; flesh thick, occasionally succulent, and edible; nutlets usually 5, thin, pointed at the ends, mostly obscurely grooved or ridged on the back; corymbs tomentose or pubescent; leaves membranaceous to subcoriaceous, broad, rounded or cuneate at base, at maturity usually pubescent or tomentose below.VIII. Molles ([page 463]). Fruit short-oblong to obovoid, scarlet; flesh usually soft and juicy; nutlets 3—5, grooved and usually ridged on the back; corymbs glabrous or tomentose; leaves thin or rarely subcoriaceous, oblong-ovate or oval, more or less acutely lobed; anthers rose or purple; rarely white in shrubby species.IX. Coccineæ ([page 488]). Fruit subglobose to short-oblong, crimson, or red tinged with green, its calyx enlarged and prominent; nutlets 5; stamens 20; anthers rose color; leaves thin, at the end of vigorous shoots as broad or broader than long.X. Dilatatæ ([page 500]). ++Leaves cuneate at base. Corymbs many-flowered; leaves subcoriaceous; fruit subglobose, rarely short-oblong; nutlets 2 or 3, obtuse at the ends, conspicuously ridged on the back; corymbs glabrous or tomentose; leaves dark green and lustrous above.XI. Rotundifoliæ ([page 504]). Corymbs few-flowered (many-flowered in one species of Bracteatæ). Fruit subglobose to short-oblong, greenish or yellowish; nutlets 3—5, usually rounded at the ends, conspicuously ridged on the back; leaves subcoriaceous, yellow-green.XII. Intricatæ ([page 508]). Fruit subglobose, red or orange-red; nutlets 3—5, slightly grooved on the back; stamens 20; anthers rose color; leaves thin, incisely lobed.XIII. Pulcherrimæ ([page 511]). Fruit subglobose to short-oblong, ½′—⅝′ long; nutlets 3—5, narrowed at the ends, prominently ridged on the back; corymbs villose; bracts large and conspicuous; calyx-lobes foliaceous; stamens 20; anthers yellow; leaves dark green, lustrous and scabrate above, their petioles sparingly glandular through their whole length.XIV. Bracteatæ ([page 513]). †Petioles long or short, leaves and corymbs glandular; corymbs usually simple, few-flowered; fruit subglobose to short-oblong or obovoid, green, orange, or red, flesh usually hard and dry; branchlets conspicuously zigzag.XV. Flavæ ([page 515]). **Veins of the leaves extending to the points of the lobes and to the sinuses; corymbs many-flowered; stamens usually 20. Fruit depressed-globose to short-oblong, not more than ¼′ long, scarlet; nutlets 2—5, prominently ridged and often grooved on the back; anthers rose color or yellow.XVI. Microcarpæ ([page 530]). Fruit subglobose, ⅓′—½′ in diameter, blue or blue-black; nutlets 3—5, obtuse at the ends, slightly ridged on the back; anthers yellow; leaves cuneate at base, dark green and lustrous.XVII. Brachyacanthæ ([page 533]). 2. Nutlets longitudinal cavities on their ventral faces; flowers in many flowered compound corymbs. Fruit obovoid to subglobose or short-oblong, lustrous, orange or scarlet; nutlets 2 or 3, obtuse at the ends, prominently ridged on the back; leaves thin to subcoriaceous, mostly pubescent below.XVIII. Macracanthæ ([page 535]). Fruit short-oblong to subglobose, black; rarely chestnut color; nutlets 5, obtuse at the ends, obscurely ridged on the back; stamens 10—20; anthers pale rose color.XIX. Douglasianæ ([page 545]). Fruit subglobose, short-oblong to ovoid, scarlet; nutlets 3—5, acute at the ends, ridged on the back, ventral cavities obscure; leaves scabrate above.XX. Anomalæ ([page 547]).