xI I I. Group BRACTEAT/E Fruit bright red. (C. Asbei) HAW CCCc. Petioles, leaves and corymbs conspicuously glandu lar; corymbs few-flowered; fruit to 3- inch long, flesh hard, dry; branches zizag.
XiIV. Group FLAVIE Bark deeply furrowed; leaves diamond shaped, thick, shining, with short winged petiole; corymbs velvety, with 3 to 6 flowers, stamens to, an thers yellow; fruit late, dull orange red, flattened. (C. aprica) HAW BB. Veins of leaves extending to sinuses as well as to points of lobes; corymbs many-flowered; stamens 20.
C. Fruit flattened to oblong, pea size, scarlet; nutlets to 5, prominently ridged at back; anthers rose coloured or purple.
XV. Group MICROCARIVE D. Leaves round, deeply 5 to 7 cleft.
(C. apiifolia) PARSLEY HAW DD. Leaves heart shaped.
(C. cordata) WASHINGTON THORN CC. Fruit flattened, to 3 inch long, red, blue or blue black nutlets 3 to 5, obtuse at ends, slightly ridged at back; leaves dark and lustrous.
XvI. Group BRACHYACANTHA Leaves lanceolate; thorns stout; fruit bright blue. (C. brachyacantha) POMETTE BLEUE AA. Nutlets grooved in front.
B. Fruits 3 to )! inch long, erect, lustrous, orange or scarlet; nutlets 2 to 3, blunt at ends, ridged on back; leaves downy below.
XvI I. Group TOMENTOS/E C. Fruit pear shaped, translucent, orange red, leaves 2 to 5 inches long, grey-green, tomentose below; thorns inches long, slender.
(C. tomentosa) PEAR HAW CC. Fruit, pea-like, crimson, leaves 2 to 3 inches long, dark, lustrous, tapering; thorns 23 to 4 inches long, curved. (C. inacracantba) LONG-SPINE HAW BB. Fruit nearly globular, 3- inch long, black; nutlets 5, blunt at ends, faintly ridged on back; stamens 2o; leaves leathery.
XvIII. Group DOUGLASIANAE Leaves variable in form, fruit many in a cluster, lustrous, sweet. (C. Douglasii) BLACK HAW The hawthorns are a shrubby race of trees, under-sized, as a rule, with stiff, zigzag branches, set with thorns. The leaves are simple, alternate, deciduous, usually cut into sharp lobes, and saw teeth. The flowers are generally white, and set in terminal corymbs on side branchlets. The fruits are drupe-like pomes, with bony nutlets containing the seeds. As a rule fruits are red; in a few species they are orange; still fewer, yellow, blue or black. The flesh is generally mealy and dry. The nutlets are joined at their bases, and are variously grooved and ridged.
The stamens are normally five in a circle, set alternate with the petals. There may be five pairs, similarly placed. Or fifteen may occur, in two rows, twenty in three, or twenty-five in four circles. These are the typical arrangements. When not in fives, some stamens have failed to develop. The number of stamens, their arrangement and the colour of their anthers, is considered by Professor Sargent an important clue to relationship. The grooves and ridges on the nutlets form another constant and significant character on which his classification is based.
The generic name, Cratgus, is derived from kratos, the Greek word for strength, and refers to the hard, tough wood.
The centre of distribution for the hawthorns is undoubtedly the eastern United States. From Newfoundland to Mexico they abound in great variety. A few species are found on the Pacific coast and in the Rocky Mountains. Europe and Asia have a few.
It is remarkable that trees so conspicuous as these should until lately be so little known. Linnaeus named four American species. Professor Sargent described fourteen only in Vol. IV. of "The Silva of North America." In Vol. X111., the supplement, issued in 1900, seventy-three species were added to those described in Vol. IV., bringing his total up to eighty-seven. In his "Manual" published in 1905, Professor Sargent describes and gives rank as species to 128 hawthorns native to the United States. These are divided into eighteen groups by characters set forth in the key. I have chosen a typical species to illustrate each group, and added only such others as have distinction and horticultural promise. The fact that Professor Sargent knows this genus better than any one else has been my reason for borrowing his key almost un changed.
The whole story of the hawthorns and their relationships can not be told by any man now living. Nor can present knowledge and opinion on the subject be considered as final. It takes time to test the stability of species. Thousands of seeds have been collected from haws and planted in the nurseries of the Arnold Arboretum. Probably no such undertaking was ever projected and carried out. What is it all about? Take an example.