Since it comes from elevations of 8000 or 9000 feet in the mountains of Colombia and Ecuador, this species is more frost-resistant than its near relative the papaya, and in this characteristic lies its greatest interest. It has been suggested that hybridization of the two species might result in a plant which would be sufficiently hardy for regions like southern California and the shores of the Mediterranean, and yet would produce fruit nearly as good as that of the papaya. Such a hybrid has not yet been produced.

The mountain papaya resembles its more tropical relative in habit and general appearance, but it is smaller in all its parts; it grows only 8 or 10 feet high, its leaves are smaller (and deeply lobed), and its fruits are only 3 or 4 inches in length. H. F. Macmillan says: "The tree has been introduced at Hakgala Gardens, Ceylon, in 1880, and is now commonly grown in hill gardens for the sake of its fruit, being often found in a semi-naturalized state about up-country bungalows." A. Robertson-Proschowsky of Nice, France, writes, in the Petite Revue Agricole et Horticole: "It is a handsome plant, growing a few meters high, and often without branches, though the latter are developed when the top is killed by frost. For several years I have grown this species and I find it to produce good fruits, of a sweetish, acidulous, perfumed taste. They are suitable, as I have had occasion to learn from experience, for persons with weak stomachs, who cannot eat other fruits. They are particularly good for dyspeptics." Mac-millan notes that the fruit, which ripens in Ceylon throughout the year, is too acid to be used for dessert, but is very agreeable when stewed and can be made into jam and preserves.

The requirements of the plant are much the same as those of the papaya, except in regard to climate. It withstands 28° above zero without serious injury. The seeds are sown in the same manner as those of the papaya.

There are other species of Carica in tropical America, many of them as yet little known, which may be of value in connection with papaya breeding. C. quercifolia, Benth. and Hook., with leaves like those of the English oak, is even hardier than the mountain papaya, but its fruit, the size of a date, is worthless. There appear to be in Ecuador several species closely resembling C. candamarcensis, but some of them may be nothing more than varieties of the latter.