In the Moorpark, and generally in the Hemskirke, the stone presents a singular character in being perforated, with a bundle of fibres passing through the perforation from end to end. The most constant and important character, according to Thompson, is whether the kernel is bitter or sweet: yet in this respect we have a graduated difference, for the kernel is very bitter in Shipley's apricot; in the Hemskirke less bitter than in some other kinds; slightly bitter in the Royal; and "sweet like a hazel-nut" in the Breda, Angoumois, and others. In the case of the almond, bitterness has been thought by some high authorities to indicate specific difference.
In N. America the Roman apricot endures "cold and unfavourable situations, where no other sort, except the Masculine, will succeed; and its blossoms bear quite a severe frost without injury." (10/68. Downing 'The Fruits of America' 1845 page 157: with respect to the Alberge apricot in France see page 153.) According to Mr. Rivers (10/69. 'Gardener's Chronicle' 1863 page 364.), seedling apricots deviate but little from the character of their race: in France the Alberge is constantly reproduced from seed with but little variation. In Ladakh, according to Moorcroft (10/70. 'Travels in the Himalayan Provinces' volume 1 1841 page 295.) ten varieties of the apricot, very different from each other, are cultivated, and all are raised from seed, excepting one, which is budded.
PLUMS (Prunus insititia).
(FIGURE 43. PLUM STONES, of natural size, viewed laterally. 1. Bullace Plum. 2. Shropshire Damson. 3. Blue Gage. 4. Orleans. 5. Elvas. 6. Denyers Victoria. 7. Diamond.)
Formerly the sloe, P. spinosa, was thought to be the parent of all our plums; but now this honour is very commonly accorded to P. insititia or the bullace, which is found wild in the Caucasus and N.-Western India, and is naturalised in England. (10/71. See an excellent discussion on this subject in Hewett C. Watson 'Cybele Britannica' volume 4 page 80.) It is not at all improbable, in accordance with some observations made by Mr. Rivers (10/72. 'Gardener's Chronicle' 1865 page 27.), that both these forms, which some botanists rank as a single species, may be the parents of our domesticated plums. Another supposed parent-form, the P. domestica, is said to be found wild in the region of the Caucasus. Godron remarks (10/73. 'De l'Espece' tome 2 page 94. On the parentage of our plums see also Alph. De Candolle 'Geograph. Bot.' page 878. Also Targioni-Tozzetti 'Journal Hort. Soc.' volume 9 page 164. Also Babington 'Manual of Brit. Botany' 1851 page 87.) that the cultivated varieties may be divided into two main groups, which he supposes to be descended from two aboriginal stocks; namely, those with oblong fruit and stones pointed at both ends, having narrow separate petals and upright branches; and those with rounded fruit, with stones blunt at both ends, with rounded petals and spreading branches. From what we know of the variability of the flowers in the peach and of the diversified manner of growth in our various fruit-trees, it is difficult to lay much weight on these latter characters. With respect to the shape of the fruit, we have conclusive evidence that it is extremely variable: Downing (10/74. 'Fruits of America' pages 276, 278, 284, 310, 314. Mr. Rivers raised ('Gardener's Chronicle' 1863 page 27) from the Prune-peche, which bears large, round, red plums on stout, robust shoots, a seedling which bears oval, smaller fruit on shoots that are so slender as to be almost pendulous.) gives outlines of the plums of two seedlings, namely, the red and imperial gages, raised from the greengage; and the fruit of both is more elongated than that of the greengage. The latter has a very blunt broad stone, whereas the stone of the imperial gage is "oval and pointed at both ends." These trees also differ in their manner of growth: "the greengage is a very short- jointed, slow-growing tree, of spreading and rather dwarfish habit;" whilst its offspring, the imperial gage, "grows freely and rises rapidly, and has long dark shoots." The famous Washington plum bears a globular fruit, but its offspring, the emerald drop, is nearly as much elongated as the most elongated plum figured by Downing, namely, Manning's prune.