5. Prunus hortulana L.H. Bailey (wild goose plum, hortulan plum)

P. hortulana var. mineri L.H. Bailey

Pl. 537 c, d; Map 2475

Plants shrubs, 3–5 m tall, or more commonly trees to 6(–10) m tall, sometimes suckering to form thickets. Branches moderately thorny. Twigs glabrous, producing pseudoterminal winter buds (these usually in a cluster of 2 or 3 at the tip). Petioles 6–20 mm long, hairy on the upper side, often with 1 to several glands near the tip. Leaf blades (5–)7–11(–13) cm long, (2.0–)3.0–5.5 cm wide, more than 2 times as long as wide, lanceolate to oblong-lanceolate, oblanceolate, or narrowly elliptic, broadly angled to rounded at the base, long-tapered at the tip, the margins finely and simply to doubly toothed, the blunt incurved teeth gland-tipped, the upper surface glabrous or with a few hairs along the midvein, the undersurface sparsely to moderately hairy along the main veins. Inflorescences produced when the leaves are about half-grown, umbellate clusters of 2–4(5) flowers per bud, the flower stalks 8–20 mm long, glabrous. Flowers with the hypanthium 2–3 mm long, bell-shaped, glabrous. Sepals 1.5–3.0 mm long, ascending to reflexed at flowering, ovate, the margins glandular-toothed, the inner surface densely short-hairy below the midpoint. Petals 4–9 mm long, obovate, white. Fruits 20–30(–40) mm long, globose, shallowly longitudinally grooved on 1 side, the surface red to yellowish, with conspicuous white dots, glabrous, not or only slightly glaucous, the fleshy layer well-developed, the stone ovoid-ellipsoid, somewhat flattened, the surface shallowly pitted. 2n=16. March–May.

Scattered to common nearly throughout the state, but relatively uncommon in the northwestern portion (eastern U.S. west to Nebraska and Texas). Banks of streams and rivers, margins of ponds, lakes, and sinkhole ponds, upland prairies, edges of bottomland prairies, and swamps; also pastures, fencerows, old homesites, railroads, and roadsides.

This species is sometimes cultivated as an ornamental, and a number of cultivars exist. Steyermark (1963) noted the existence in southwestern Missouri of occasional putative hybrids between P. hortulana and P. mexicana, to which he applied the name P. palmeri Sarg.

Most recent floristic works for the eastern half of the United States have included the wild goose plum (P. munsoniana W. Wight & Hedrick; Pl. 536 f–h) as a distinct species, and it is the source of a number of ornamental cultivars. Steyermark (1963) recorded it from scattered populations nearly throughout the state. However, in practice, the distinctions between P. hortulana and P. munsoniana (earlier-flowering relative to leaf development and inflorescences on long branches [vs. short spur shoots] in P. munsoniana, as well as its lateral [vs. terminal] gland-tips on the leaf teeth and a usually strongly suckering habit) have been difficult to apply to specimens and trees in nature. The molecular phylogenetic studies of Rohrer (2006) have provided evidence that plants attributed to P. munsoniana constitute a series of fertile hybrids between P. angustifolia and P. hortulana.