Rutaceae

Rue Family

Common Hoptree

FAMILY: Rue family (Rutaceae) – Ptelea genus.

SPECIES: #1 common hoptree (Ptelea trifoliata L. var. angustifolia (Benth.) M. E. Jones = Ptelea angustifolia Benth.). #2 common hoptree (Ptelea trifoliata L. var. mollis Torr. & A. Gray = Ptelea tomentosa Raf.). #3 common or pallid hoptree (Ptelea trifoliata L. var. pallida (Greene) V. L. Bailey = Ptelea pallida Greene).

TO UTILIZE AS FOOD: The young, wafer-like fruits (samaras) of common hoptree (also known as wafer ash) are infrequently reported to be edible. Other parts are inedible, but they can be used as medicine.

In reference to Ptelea tomentosa Edward Castetter (1935-a p. 47) states, “The young fruits of this species are known at San Felipe as chibanini and commonly eaten by children.” No more details are given. Castetter was referring to the San Felipe Indian Reservation in north-central New Mexico. Subsequent authors often cite Castetter as the original reference to edibility. Francois Couplan (p. 310) indicates that the bitter, aromatic fruits of Ptelea trifoliata, P. angustifolia, and P. pallida can be ground, sifted, and mixed with flour to make bread. Common hoptree “fruits” are basically just dry wings surrounding a few seeds. The only chewable portion is the seed inside. Based on Daniel Moerman’s comprehensive review of ethnobotanical literature, common hoptree fruits were not used as food by Native Americans, with the exception at San Felipe. In 1876, Asa Gray (p. 110) reported that the fruits were used as a substitute for hops in making beer. American settlers pioneered this use of hoptree fruits, which were added to impart bitterness and prevent spoilage, just as hops are used today. Settlers also used hoptree fruits in combination with other ingredients (such as potatoes, sugar, and water) to make yeast for baking and brewing.

Young fruits (samaras) of common hoptree (P. trifoliata) are soft, green, aromatic, resinous, and bitter. They smell good, but the flavor may not strike everyone as food-like. No grocery store foods taste similar, except for the rinds of citrus fruits. Comparisons to wild foods suggest alliances with cottonwood buds, cow parsnip seeds, and unripe sumac fruits. Boiling improves the strong flavor, usually enough to render the samaras palatable. Marinating the samaras in vinegar also improves the flavor. Gathering substantial quantities is easy and best done when the samaras first appear, which tends to be toward the end of summer. They can be gathered as vegetables until fibers develop in the wings or portions protecting the seeds become too tough. The development of wings and transition from soft to tough happens quickly, so the ideal gathering time is brief. Mature samaras are dry, papery, and wafer-like. They have no fleshy portions, and therefore no food value. Only young samaras can realistically serve as food. Mature samaras can be chewed, but only the seeds inside have food value. References stating “the fruits” are edible, presumably mean the young fruits, but they could also mean the seeds. Austin (p. 252) interpreted Castetter’s statement quoted above to mean the seeds. Certainly, in fruits of any age, the seeds represent the bulk of chewable material. It’s relevant to note that Castetter said the young fruits were “eaten by children” rather than gathered as a staple food item, and the general lack of references to this wild food suggests that it’s only of minor importance.

Seeds of common hoptree (P. trifoliata) are not reported to be edible. However, since the fruits are edible and the seeds are the only portion of the fruits that are chewable, it’s reasonable to assume that references to the fruits include the seeds. Mature seeds are typically white with tan skins and surrounded by thin, flaky, black material. Each fruit is filled with 1-3 seeds. Fresh seeds are soft, delicate, and somewhat nut-like. They have a texture comparable to sunflower seeds. Removing the seeds from the fruits is difficult. No processing techniques seem to be effective due to the tough coverings around the seeds. Chewing the seeds out of the fruits is possible, but unwise because the wings have irritating fibers. Aromatic resins impart a distinctive flavor. The flavor is bitter, but this bitterness can be subdued by cooking. Hoptree seeds taste similar to hoptree fruits described above, except for an additional oily component. The fruits mature in autumn and often persist into winter, a time when few other resources are available to foragers.

NOTES: The common hoptree assessments were based primarily upon trees from the Gila National Forest in western New Mexico. According to Fuller (pp. 227-228), all parts of common hoptree contain phototoxins (see the parsley family overview) that can potentially sensitize the skin to sunlight, but the rue family is an infrequent source of toxicity.

IDENTIFICATION: Currently, only 2 species of the Ptelea genus are recognized in the United States. California hoptree (P. crenulata) is limited to California, but common hoptree (P. trifoliata) grows just about everywhere. Former species occurring in the Southwest are now classified as subspecies or varieties of common hoptree. Although outdated at this point in time, Greene from 1906 provides a comprehensive key describing 59 species.

Description of common hoptree (Ptelea trifoliata): FORM thornless, aromatic, deciduous shrub or small tree about 3-6 meters tall; LEAVES compound; alternate; leaflets 3-5, lance-ovate, 2-8 cm long; margins smooth or finely toothed; surfaces gland-dotted; FLOWERS regular, unisexual, ovary superior, and arranged in clusters; sepals 4-5; petals 4-5, free, white; pistils 1; styles 1; stigmas 2-3; stamens 4-5; FRUITS samaras normally flat, circular, winged, and papery; sometimes 3-winged; SEEDS 1-3 per fruit, reddish-brown, and pointed; HABITAT found in the mountains of Arizona and New Mexico, and the eastern United States; blooming April and May.

REFERENCES: #1 common hoptree (Ptelea trifoliata var. angustifolia = Ptelea angustifolia): immature fruits Couplan (p. 310). #2 common hoptree (Ptelea trifoliata var. mollis = Ptelea tomentosa Raf.): immature fruits Castetter (1935-a p. 47), Couplan (p. 310), Ebeling (p. 501), Moerman (p. 203), and Yanovski (p. 40). #3 common hoptree (Ptelea trifoliata var. pallida = Ptelea pallida): immature fruits Couplan (p. 310).