Rubus nelsonii Rydb.

Rubus nelsonii Rydberg, sp. nov
Stems perennial, reclining, 2-4 m. long, terete, purplish, more or less pubescent when young, armed with rather weak small prickles; leaves quinate or the upper ternate; stipules subulate, 5-7 mm. long; petioles, petiolules, and midveins pubescent and armed with recurved prickles; leaflets lance-ovate, long-acuminate, 3-7 cm. long, sharply serrate, with lanceolate teeth, rounded or acute at the base, soon glabrate above, sparingly pubescent beneath; petiolule of the terminal leaflet about 1 cm. long, those of the lateral ones 1-2 mm. long or obsolete; lateral veins 7-10 on each side; inflorescence rather few-flowered, leafy-bracted, pubescent and more or less prickly; sepals ovate-lanceolate, 7-8 mm. long, apiculate, tomentose on both sides; petals white, elliptic-obovate, 10-12 mm. long; fruit subglobose, dark-purple; drupelets 15-20, large and pulpy; putamen 3 mm. long and nearly as broad, strongly reticulate.
Type collected on the west slope of Zempoaltepec, Oaxaca, Mexico, July 5-13, 1894, E. W
Nelson 580 (U. S. Nat. Herb.).

Rubus nelsonii is an uncommon Mexican species of brambles in the rose family. It has been found only in the State of Oaxaca in southern Mexico.

Rubus nelsonii is a perennial with stems up to 4 meters long, reclining on walls, rocks, or other vegetation. Stems are purple, hairy and with relatively few, weak curved prickles. Leaves are compound with 3 or 5 leaflets. Flowers are white. Fruits are dark purple.