Prunus simonii × Prunus triflora × Prunus cerasifera × Prunus munsoniana
1. Cal. State Bd. Hort. 53 fig. 1897. 2. Burbank Cat. 1899. 3. Waugh Plum Cult. 225. 1901. 4. Rural N. Y. 62:582. 1903.
Late Klondike 1.
Shiro has been in the hands of fruit-growers too short a time to permit a just estimate of it to be made. As the variety grows on the grounds of this Station, the fruits are large and handsome in form and color, as is well shown in the illustration. The flavor lacks character and is almost insipid but the flesh is tender, melting and juicy and so translucent that the pit can be seen through the flesh. Despite the flavor, the plum is pleasant to eat and may be ranked as good in quality. Those who have had experience say that the variety ships very well if not fully mature but quickly goes down after ripening; the plums are also quite susceptible to brown-rot. The trees of this variety at Geneva are quite as vigorous, hardy, and productive as any of the sorts which Mr. Burbank gives as progenitors of Shiro and will generally, it is believed, surpass any of them in these respects. It may here be remarked that of the four species from which Shiro is supposed to have come, it most resembles Prunus triflora in both tree and fruit though the leaves have some resemblance to those of Prunus cerasifera. Shiro is still, so far as New York is concerned, in the list of plums deserving trial but with the chances against its becoming of great value either for home or commercial plantations.
This is another of Burbank’s plums and is said to be a descendant of Robinson, (Prunus munsoniana,) Myrobalan, (Prunus cerasifera), and Wickson, (a cross of Prunus triflora and Prunus simonii) from seed of Wickson. Burbank in his catalog for 1889 says that the tree resembles a Myrobalan in foliage, growth and general appearance. But as the variety grows at this Station it has all the appearances of a Triflora. Shiro was described in the California State Board of Horticulture Report for 1898 and the following year it was introduced by the originator.
Tree large, vigorous, upright-spreading, tender to cold, productive; branches smooth, somewhat thorny, dull ash-gray, with few, small lenticels; branchlets slender, above medium in length, with short internodes, greenish-red changing to brownish-drab, glabrous, with inconspicuous, scattering, small lenticels; leaf-buds small, very short, obtuse, strongly appressed.
Leaves folded upward, obovate, one and five-sixteenths inches wide, two and three-quarters inches long, leathery; upper surface faintly rugose, glabrous, with a grooved midrib; lower surface lightly pubescent along the midrib and larger veins; apex acutely pointed, base rather acute, margin finely crenate, with small, dark glands; petiole three-eighths inch long, pubescent along one side, greenish-red, glandless or with one or two small, globose, yellowish glands on the stalk.
Blooming season early and of medium length; flowers appearing before the leaves, white; borne in clusters on lateral buds and spurs; pedicels short, glabrous, greenish; calyx-tube green, campanulate, glabrous; calyx-lobes obtuse, glandular-serrate, glabrous on the outer side, sparingly pubescent within, with a pink margin, erect; petals roundish, entire, tapering to short, abrupt claws; anthers yellow with a reddish tinge; filaments below medium in length; pistil glabrous, longer than the stamens.
Fruit very early, season short; one and one-half inches in diameter, roundish-conic, with halves equal; cavity intermediate in depth and width, flaring, regular; suture an indistinct line; apex roundish; color light yellow becoming deeper yellow as the season advances, occasionally with a blush of pink, with thin bloom; dots numerous, very minute, whitish, inconspicuous; stem three-eighths inch long, adhering to the fruit; skin thin, tough, sour, occasionally cracking, separating readily, although a thin coating of flesh is left clinging to the skin; flesh light yellow, semi-transparent, the stone being faintly visible, very juicy, fibrous, somewhat melting, sweet, mild, lacks character in flavor; good; stone clinging, seven-eighths inch by five-eighths inch in size, broadly oval, flattened, slightly elongated at the base, with rough surfaces; ventral suture faintly ridged and furrowed; dorsal suture very lightly grooved.