Ecotone Blackberry

Rubus heterophyllus Wilid. Berl. Baumz. ed. 2. 413. 1811
Rubus villosus michiganensis Card; h. H. Bailey, Evol. Nat. Fr. 374. 1898. Rubus geophilus Blanchard, Rhodora 8: 148. 1906.
Stems biennial, 2-4 m. long, prostrate from the beginning, light-green, glabrous, glandless, armed with recurved prickles; leaves of the turions 3-5-foliolate; stipules subulate, adnate at the base, 10-15 mm. long; petioles, petiolules, and veins armed with weak recurved prickles, otherwise nearly glabrous; leaflets large, light yellowish-green, slightly appressed-pubescent on both sides, short-acuminate, very coarsely and doubly serrate, entire towards the base; terminal leaflet 7-10 cm. long, broadly ovate or rounded-ovate, the lateral ones narrower and smaller, in the 3-foliolate leaves often 2-cleft; floral branches 1-2.5 dm. long; leaves 3-foliolate, or 1-foliolate in the inflorescence; leaflets oval, coarsely and doubly serrate, acute at each end, the terminal short-petioluled, the lateral ones sessile; inflorescence 1-5-flowered, more or less leaf y-bracted, slightly pubescent but not glandular; sepals broadly ovate, short-acuminate, 6-7 mm. long, puberulent without, tomentose within; petals white, elliptic, 10-14 mm. long; fruit short, oblong or globose, 16-18 mm. long, 14—16 mm. thick; drupelets 15-32, large, juicy.
Type locality: North America.
Distribution: Open dry grounds, from Maine to Connecticut, New Jersey, and Michigan.

Rubus heterophyllus is a rare North American species of flowering plant in the rose family. It has been found in eastern Canada (Québec) and in scattered locations in the eastern United States (New York, West Virginia, Maryland).

The genetics of Rubus is extremely complex, so that it is difficult to decide on which groups should be recognized as species. There are many rare species with limited ranges such as this. Further study is suggested to clarify the taxonomy.