Deciduous shrubs or trees, usually with well-developed twig-spines. Twigs moderate or rather slender, terete, pith rather small, continuous, round. Buds solitary or collaterally branched, sessile, round or oblong-ovoid, with about 6 exposed scales. Leaf-scars alternate, narrowly crescent-shaped; bundle-traces 3; stipule-scars small.
Fig. 142. Crotaegus punctata.
Crataegus is a large and exceptionally complicated genus, with more than 100 species recognized from the range of this manual. The plants, however, are very hard to identify, even from material having leaves, flowers, and fruit, and it is a hopeless task to attempt to construct a key to distinguish them in the winter state. In the present treatment, nevertheless, an effort has been made to provide winter characters for the different groups (Series) of the region. Even this has proved very difficult and the following key must be regarded as quite provisional.
Slender shrubs . 8-1. 5 m. tall with few simple or little-branched stems.
Series 2. Parvifoliae (C.uniflora Muench. )
Arborescent shrubs or trees with stout boles or bifurcating branches.
b. Usually shrubby but sometimes becoming small trees under favorable conditions.
c. Branches mostly ascending forming a narrow crown;thorns numerous, long and stout.
Series 14. Macracanthae. (C. succulenta .Link)
c. Lower branches spreading, forming rounded crowns usually as
* Based on data furnished by Ernest J. Palmer
broad as high, armed with slender thorns or sometimes nearly thorn-less.
d. Bark comparatively thin and smooth, exfoliating in small thin flakes.
Series 1. Microcarpae. (C.
d. Bark on old boles or branches comparatively thick, more or less fissured or scaly.
e. Thorns usually straight and slender, 2-3. 5 cm. long. No compound thorns.
Series 4. Pulcherrimae. (C. ancisa Beadle, etc.)
e. Thorns stouter, often curved, 3-5 cm.long. Compound thorns sometimes on boles and larger branches.
Series 3. Intricatae. (C. intricata Lange, etc.)
Usually arborescent, but sometimes appearing shrubby in young state.
c. Boles and larger branches fluted or buttressed, not round or symmetrical in cross section; thorns usually stout and strongly curved.
Series 9. Tenuifoliae. (C.
c. Boles and larger branches normally terete and symmetrical in cross section;thorns variable but not conspicuously short and curved.
d. Bark thin, pale gray, exfoliating in large plates or flakes over orange-brown or cinnamon colored inner bark. Becoming large trees in low alluvial ground; often thornless or sparingly thorny.
Series 5. Virides. (C. viridis L., etc.)
Bark thicker, becoming rough or more or less scaly, gray or gray-brown.
e. Bark on old boles thick and deeply ridged and fissured; branchlets rather stout, usually thorny. Becoming large trees in fertile uplands.
Series 12. Molles. (C. mollis
e. Bark on boles not deeply ridged or fissured,usually becoming more or less scaly. Small trees seldom over 8-10 m. tall.
f. Crown in well-developed trees broadly conical or depressed conical, often broader than high, lower branches often slightly depressed. Compound thorns often on boles and large branches.
g. Branchlets slender, glabrous, usually flexuous and quite thorny; lower branches dense and intricate; bark of old boles scaly, smooth and dark gray on branches.
Series 6. Crus-galli (C. crus-galli L., etc.)
g. Branchlets stoutish, the youngest slightly pubescent, armed with long slender thorns or nearly thornless. Bark on old boles brownish-gray, finely scaly.
Series 7. Punctatae (C. punctata Jacq., etc.Fig. 142).
f. Crown usually conical, rounded or irregular, rarely as broad as high.
g. Crown-irregular, open, of stoutish spreading branches;branchlets flexuous and thorny. Often fruiting as arborescent shrubs.
Series 13. Pruinosae. (C.
pruinosa (Wendl.) K. Koch, etc.)
g. Crown more symmetrical, usually rounded or conical in well-developed plants. Branches more numerous and intricate.
h. Trees up to 10 m.tall with wide-spreading branches; youngest branchlets reddish brown.
Series 11. Coccineae (C. pedicellate Sarg., etc.) h. Small trees seldom over 5-6 m.tall, with round or conical crowns; branchlets soon gray.
i. Bark close, slightly fissured and broken into small brownish-gray scales, growing usually in low moist or flat woods. Series 10. Silvicolae. (C. iracunda Beadle, etc.) i. Bark becoming slightly scaly, dark gray-brown, growing usually in upland thickets or rocky ground. Series 8. Rotundifoliae. (C. chrysocarpa Ashe, etc.)