Native Fruits of California

I've seen several old references about crossing Japanese or French plums to a native plum, with no indication of the species. What plants are they referring to?

Here's a plum description from The California Fruits and How to Grown Them (Edward Wickson, 1889, p. 281): "Gaviota - Burbank cross of Japanese and native American; very large, deep red; flesh yellow, firm and sweet; pit small; rather late bloomer. Favored in the Vacaville district for shipping " Native American? Native Californian?

Wickson's book has a chapter called "The Wild Fruits of California" that is helpful to know which California native fruits were known.

I've copied part of this chapter so I can [note it] with the current species names, other publications that were listed in the footnotes, and with photos of the plants.

Chapter IV

Malus fusca
from Calflora

Among fruits native to California, the apple, because of its acknowledged kingship of fruits borne on deciduous trees, may be mentioned first. On the banks of streams from Sonoma County northward, beyond the boundaries of the State, is found Native Crab-Apple of California, the "Oregon crab-apple," [noted as Pirus rivularis. Pyrus rivularis is now known as Malus fusca] described as a shrub or small tree, but which, in favorable situations, attains good size. Such trees are reported from the neighborhood of Crescent City, Del Norte County, with bodies one foot in diameter, with spreading tops, loaded with small, oval fruit, of a golden color when ripe ["Wild plums and crab apples", Pacific Rural Press, Vol. 4, p. 198, Sept. 28, 1872]. This fruit is eaten by the Indians, and was used in early times for jelly making by the white settlers. The tree is generally found on cold, wet land, bordering ponds, streams, and marshes. 

Prunus subcordata

The California wild plum [Prunus subcordata] has attracted considerable attention ever since the advent of the gold seekers. It was early noticed that there are at least two varieties [A. Kellogg, in Hutching's Magazine, Vol. 5, p. 7 "California Wild Plum"] of the species. They are found well distributed over the uplands of the coast and interior, becoming, however, more abundant, and bearing more pulpy fruit toward the northern part of the State. One variety is round, and sometimes nearly an inch in diameter; the other, a little smaller, oblong, and almost the shape and color of a Damson when ripe. The fruit is borne upon scraggy, many branched shrubs, from three to ten feet high, which generally grow in patches at the head of ravines, on rocky hills, and in open woods. The two varieties are found associated, and both are esteemed by Indians and whites.

Early efforts were made to domesticate these wild plums, and they showed themselves susceptible of improvement by cultivation to a certain extent. In 1856 there was on the Middle Yuba River, not far from Forest City, in Sierra County, a wayside establishment, known as "Plum Valley Ranch," so called from the great quantity of wild plums growing on and about the place. The plum by cultivation gave a more vigorous growth and larger fruit [Report California Agricultural Society, 1858, p. 183]. Transplanted from the mountains into the valley they are found to ripen earlier [Cal. Culturist, 1858, p. 242]. Transplanted from the mountains to a farm near the coast, in Del Norte County, they did not thrive [Pacific Rural Press, Vol. IV, p. 198]. One variety, moved from the hills near Petaluma, in 1858, was grown as an orchard tree for fifteen years, and improved both in growth and quality of fruit by cultivation [Pacific Rural Press, Vol. IV, p. 163]. The attention of fruit growers was early drawn to the possible value of the wild plum as grafting stock, and it is reported to have done fairly well on trial [Pacific Rural Press, Vol. IV, p. 198]. Recently excellent results have been reported from the domestication of the native plum in Nevada County, and fruit shown at the State fair of 1888 gave assurance that by cultivation and by selecting seedlings valuable varieties can be obtained. It is stated [Letter from S. B. Davidson, Downieville] that in Sierra County the wild plum is the only plum which finds a market at good prices and that cultivated gages, blue and egg plums scarcely pay for gathering. The wild plum makes delicious preserves.

Oso berry
from Calflora

Classed also among the plums is the "oso berry," or, as it is sometimes called, the "California false plum," [Nuttalia cerasiformis, now Oemlaria cerasiformis] a shrub or small tree, from two to fifteen feet in height, found in moist places and on the north slopes of hills, from San Luis Obispo northward. It has bark smooth and brown like a plum or cherry. The fruit when ripe is clothed with a handsome blue bloom, and is an oblong, plum-like, pulpy fruit, beautiful, but rather bitter. This species has also been used as grafting stock, with the effect of dwarfing and causing early bearing [ Pacific Rural Press, Vol. IV, p. 198.] of the varieties worked upon it.

We have several species of Prunus, which may be called wild cherries. The first is commonly called the wild cherry, [Prunus demissa, now Prunus subcordata] and is an erect, slender shrub, two to twelve feet high, bearing on a raceme a round, purplish-black or red fruit, with a round stone. The fruit is edible, but somewhat astringent. This species occurs throughout the State, except near the coast, extends northward to the Columbia River, and eastward to the Rocky Mountains. This species very closely resembles the choke-cherry and the wild black cherry of the Atlantic States. Some observers, however, protest against calling it a choke-cherry, be- cause it has none of the properties of that cherry. The wild fruit is used to some extent for marmelade [J. G. Lemmon, in Rural Press, Feb. 22, 1879.]. It has been cultivated to some extent in places near its habitat. In 1858 there was quite a plantation of it in the foot-hills east of Marysville. [Agricultural Society Report, I 58, p. 174.] As it grows well on cool north hill-sides in the Southern counties, it has been suggested [Rural Californian, Vol. X, p. 107] that the improved cherries, which are, as a rule, not satisfactory so far as tried in that part of the State, might succeed if planted in the places where the wild cherry thrives ; or the wild roots might prove trustworthy and valuable stocks on which to work the improved varieties. They were used for this purpose in Oregon in 1850 because there were no other cherry stocks available. An excellent growth of graft was secured, but the stock was condemned because of suckering. [Seth Lewelling, in N.W. Horticulturist, November, 1887]

Prunus emarginata,
from Calflora

There is another species [Prunus emarginata] which sometimes becomes a tree twenty-five feet high, bearing fruit in an umbel or true cherry fashion. The fruit is roundish and black, and about one-third of an inch in diameter, very bitter and astringent. From its bearing habit it has been suggested as worth trial as a stock for improved cherries. 

Prunus ilicifolia
from Wikipedia

The California "evergreen cherry," [P. ilicifolia] or " islay," early attracted attention for the beauty of its shining dark green foliage, which somewhat resembles holly. The fruit was shown at the first horticultural fair in San Francisco, in 1853, and was described as of delicate flavor, with a kernel "almost equal in flavor to the almond." [Alta, Oct. 7, 1853.] The plant is now grown as an ornamental shrub and as a hedge plant. 

Prunus lilicifolia ssp. lyonii from CNPS

There is on the islands of Catalina and Santa Cruz, off the coast of Southern California, an evergreen cherry [P. occidentalis is footnoted, but more likely Prunus ililcifolia ssp. lyonii?] which is much superior to the related species on the mainland. It is described ["Studies in Botany of California" by E. L. Greene. Vol. VI, p. 396] as a tree fifteen to twenty-five feet high, with compact and well-rounded head, bearing a fruit three-quarters of an inch in diameter, dark red-purple, the thin pulp sweet, with a bitter almond flavor, but no acidity or astringency. This fruit has been mentioned as worthy of cultivation. [Gustav Eisen, in Pacific Rural Press, Vol. XXVI. p. 8.] 

Prunus andersonii
from Wikipedia

Perhaps the most interesting wild fruit of California is the wild peach, or wild almond [Prunus Andersonii] which is found on the eastern slopes of the Sierra Nevada Mountains. It is a low, spreading shrub, one to six feet high. The fruit more nearly resembles the peach than does that of any other of our native species of the genus Prunus, and is, in fact, the nearest approach in the American flora to the old genus Amygdalus of the Old World, ["California Botany," Vol. I, p. 168.] to which the true peach, nectarine, and almond belong. The late Dr. Kellogg contended that the shrub was really a species of Amygdalus, but it is stated that this claim cannot be approved. 

[article continues....grapes, berries, nuts]

The following are my efforts to sort out the names and provide additional information:

1. Oregon Crabapple was noted here as Pirus rivularis (Hortus 3 has Pyrus rivularis noted as now Malus fusca): Calflora for Malus fusca, Coastal Northern California.
2. Prunus subcordata - California Wild plum - Calflora, Las Pilitas (Plant next to bird bath, tolerates flooding.), reportedly very tasty. 
3. Wild Crabapple (Peraphyllum ramosissimum): Calflora. Sierran

The following are references in the original chapter:

1. A. Kellogg, in Hutching's Magazine, Vol. 5, p. 7 "California Wild Plum"
2. A. Kellogg, in Hutching's Magazine, Vol. 5, p. 9 "California False Plum, Nuttallia Cerasiformis"
3. "Wild Plums and Crab Apples." (Pacific Rural Press, Volume 4, Number 13, 28 September 1872) referred back to 1858 California Culturalist, p. 11 and p. 242.

Further references

1. Sketch of the Evolution of Our Native Fruits, L.H. Bailey