2. Morus rubra L. (red mulberry)

M. murrayana Saar & Galla

M. rubra var. murrayana (Saar & Galla) Saar

Pl. 458 e, f; Map 2082

Twigs reddish brown to light greenish brown, minutely hairy or nearly glabrous, the lenticels usually pale. Petioles 1–4 cm long. Leaf blades 7–28 cm long, 7–25 cm wide, unlobed or shallowly to deeply (2)3–5-lobed, abruptly tapered to a sharply pointed tip, the lateral lobes (when present) short-tapered to slender tips, truncate to shallowly cordate at the base, the upper surface smooth to more commonly moderately to strongly roughened, dull, with scattered inconspicuous hairs, the undersurface sparsely to densely short-hairy, smooth or somewhat felty to the touch Staminate inflorescences 30–50 mm long, cylindric. Pistillate inflorescences 8–12 mm long, short-cylindric. Multiple fruits 1.0–1.9(–3.5) cm long, 0.6–0.8(–1.2) cm wide, short-cylindric, dark purple to black, the achenes 1.5–2.0 m long. 2n=28. April–May.

Common nearly throughout the state, except in the far northwestern and southeastern corners (eastern U.S. west to Nebraska and Texas; Canada). Bottomland forests, mesic upland forests, banks of streams, rivers, and spring branches, margins of sinkhole ponds, ledges and tops of bluffs, edges of glades, and savannas; also fencerows, pastures, and roadsides.

Deciduous woods and edges of pastureland, often along streams, roadsides, and railroads.

The wood of red mulberry is light and durable, and it has been used for fence posts, barrels, boats, and tools of various kinds. The inner bark yields good-quality fiber that has sometimes been used in the manufacture of cordage and cloth. Native Americans used red mulberry medicinally as a laxative and purgative, and also to treat dysentery, urinary problems, and ringworm (Moerman, 1998). Red mulberry occasionally has been used to feed silkworms, but is considered much inferior to white mulberry for this purpose.

Unfortunately, M. rubra recently has been redescribed under a new name, M. murrayana. The descriptions and illustrations of the supposed new species given by Galla et al. (2009) are a perfect match for typical M. rubra. The descriptions and illustrations labeled M. rubra in their paper clearly are not that species. Instead, they appear to be represent a misdetermination of the hybrid between M. alba and M. rubra. The controversy was addressed recently by Nepal et al. (2012) using both morphological and molecular characters, and an attempt by Saar et al. (2012) to reinterpret their taxon as a variety of M. rubra was unconvincing. Morus murrayana is thus treated as a synonym of M. rubra in the present work.