Prunus subcordata |
Prunus rivularis |
|
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Klamath plum, Oregon plum, Pacific plum, Sierra or Klamath or Pacific plume, Sierra plum, western plum |
creek plum, creek plume, hog plume |
|
Habit | Shrubs or trees, often suckering, 10–30(–60) dm, sometimes thorny. | Shrubs or trees, usually suckering, 10–80 dm, thorny. |
Twigs | with axillary end buds, glabrous or hairy. |
with axillary end buds, glabrous. |
Leaves | deciduous; petiole 4–18 mm, glabrous or hairy, usually glandular distally, glands 1–3, discoid; blade elliptic, oblong-ovate, or suborbiculate, 2–5(–6.5) × 1.3–3.5(–4.5) cm, base rounded or subcordate, margins singly to doubly serrulate, teeth blunt, glandular, apex usually obtuse to rounded, rarely acute, abaxial surface glabrous or hairy, adaxial glabrous or appressed-hairy. |
deciduous; petiole 7–21 mm, glabrous or sparsely hairy on adaxial surface, glandular distally, glands 1–4; blade lanceolate, oblong-lanceolate, or elliptic to narrowly elliptic, usually folded along midribs, 4–11 × 1.5–5 cm, base obtuse to rounded, margins singly to doubly crenate-serrulate, teeth blunt, glandular, glands inconspicuous, blackish, apex usually acuminate, sometimes acute, abaxial surface glabrous or ± hairy along midribs and veins, adaxial usually glabrous, rarely midribs hairy. |
Inflorescences | 2–5-flowered, umbellate fascicles. |
2–4-flowered, umbellate fascicles. |
Pedicels | 5–15 mm, glabrous or hairy. |
3–15 mm, glabrous. |
Flowers | blooming at leaf emergence; hypanthium campanulate, 2–3.5 mm, glabrous or hairy externally; sepals broadly spreading to reflexed, obovate, 2.2–4(–5) mm, margins glandular-toothed, sometimes obscurely so, sometimes ciliate, surfaces glabrous or hairy; petals white, oblong-obovate, 5–10 mm; ovaries usually glabrous, rarely hairy. |
blooming before or at leaf emergence; hypanthium campanulate, 2–3 mm, usually glabrous, rarely glabrate, externally; sepals broadly spreading to reflexed, oblong-ovate, 1.5–2.5 mm, margins glandular-toothed, abaxial surface glabrous or sparsely hairy, adaxial densely hairy at bases; petals white, obovate, 4–7 mm; ovaries glabrous. |
Drupes | usually red to reddish purple, sometimes yellow, globose to ellipsoid, 15–25 mm, usually glabrous, rarely puberulent; mesocarps fleshy; stones ovoid, ± flattened. |
usually red, sometimes yellowish orange, with white dots, not or only slightly glaucous, globose, 12–25 mm, glabrous; mesocarps fleshy; stones ovoid to subglobose, ± flattened. |
Prunus subcordata |
Prunus rivularis |
|
Phenology | Flowering Mar–May; fruiting Aug–Sep. | Flowering Mar–Apr; fruiting Jul–Sep. |
Habitat | Stream banks, dry rocky slopes, chaparral, pine-oak and juniper-oak woodlands | Stream banks, roadside thickets, prairie hillsides, borders of woods |
Elevation | 100–1900 m (300–6200 ft) | 200–1000 m (700–3300 ft) |
Distribution |
CA; OR
|
AL; AR; CA; CO; GA; IL; IN; KS; KY; LA; MD; MO; MS; NC; NJ; OH; OK; PA; TN; TX
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Discussion | Prunus subcordata shows variation in color, size, indument, and palatability of fruits, which has been the basis for recognition of taxonomic segregates. Variety kelloggii was described as a larger plant with less hairy foliage than in typical P. subcordata, and its fruits are yellow, larger, sweeter, and more pulpy. Variety rubicunda is a smaller shrub with bright red, bitter fruits. Most noteworthy is var. oregana with densely hairy ovaries and puberulent fruits, recorded only from the sparsely inhabited border region between northeastern California and adjacent Oregon. Specimens in herbaria are few and recent collections are lacking. The assignment of P. texana with hairy fruits to the plums (J. Shaw and R. L. Small 2005) makes this variant all the more interesting. Field study and collection followed by morphologic, genetic, and molecular study are needed to clarify its systematic position and significance. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Prunus munsoniana is here placed in synonymy with P. rivularis, greatly expanding the range of the latter compared to its traditional treatment. Descriptions of P. munsoniana and P. rivularis differ mostly in size of the plants, leaves, and floral structures. As suggested by G. M. Diggs et al. (1999), P. munsoniana is simply a larger version of P. rivularis. Evidence from analysis of DNA sequences of two nuclear genes in native plums (J. R. Rohrer et al. 2008) indicates that Prunus rivularis may be an allopolyploid. Three plants sequenced from Texas contained alleles seemingly derived from P. angustifolia on the one hand and P. hortulana (or P. murrayana) on the other. Further, two individuals determined as P. munsoniana, one each from Pennsylvania and Texas, had sequences very similar to those of P. rivularis. Other specimens in herbaria labeled as Prunus munsoniana include hybrids between P. americana and P. angustifolia, as well as individuals of P. hortulana that bloom before the leaves emerge or that sucker freely. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 377. | FNA vol. 9, p. 382. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Amygdaleae > Prunus | Rosaceae > subfam. Amygdaloideae > tribe Amygdaleae > Prunus |
Sibling taxa | ||
Synonyms | P. subcordata var. kelloggii, P. subcordata var. oregana, P. subcordata var. rubicunda | P. munsoniana, P. reverchonii |
Name authority | Bentham: Pl. Hartw., 308. (1849) | Scheele: Linnaea 21: 594. (1848) |
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