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Rubus bartonianus

Barton's raspberry, bartonberry

Pennsylvania blackberry, ronce de pennsylvanie

Habit Shrubs, 8–25 dm, unarmed. Shrubs, 10–30 dm, armed.
Stems

erect, sparsely short-hairy, glabrescent, eglandular, not pruinose.

biennial, erect to arching, glabrous or sparsely to densely hairy, eglandular or sparsely to moderately, rarely densely, sessile- to short-stipitate-glandular, not pruinose;

prickles sparse to dense, erect or slightly retrorse, stout, 4–10 mm, broad-based.

Leaves

deciduous, simple;

stipules lanceolate, 4–6 mm;

blade cordate to broadly ovate, (2–)2.5–4(–5) × (2.5–)3.5–4.5(–5.5) cm, base deeply cordate, 3–5-lobed, lobe apices acute to obtuse, margins coarsely doubly dentate, abaxial surfaces glabrous or sparsely hairy, eglandular or sparsely stipitate-glandular.

deciduous, palmately compound, not lustrous;

stipules filiform to narrowly lanceolate, (3–)5–15(–20) mm;

leaflets (3–)5(–7), terminal ovate to lanceolate, 5–15 × 3–13 cm, base rounded to shallowly cordate, unlobed, margins finely to coarsely singly or doubly serrate, apex acuminate to long-attenuate, abaxial surfaces green, usually with retrorse prickles on midveins, moderately hairy, eglandular or sparsely to moderately sessile- to short-stipitate-glandular along veins.

Inflorescences

1-flowered.

terminal on short shoots, usually appearing axillary, (2–)5–12(–16)-flowered, cymiform, racemiform, or thyrsiform.

Pedicels

moderately hairy, eglandular or sparsely stipitate-glandular.

unarmed or prickles sparse, erect, glabrous or sparsely to densely hairy, eglandular or sparsely to moderately sessile- to short-stipitate-glandular.

Flowers

bisexual;

petals white, obovate, (15–)20–25 mm;

filaments filiform;

ovaries glabrous, styles clavate, villous.

bisexual;

petals white, usually obovate to elliptic, rarely suborbiculate, 8–40 mm;

filaments filiform;

ovaries glabrous.

Fruits

deep red, hemispheric, to 1 cm;

drupelets 10–30, coherent, separating from torus.

black, globose to cylindric, 1–2 cm;

drupelets 10–100, strongly coherent, separating with torus attached.

2n

= 14, 21, 28, 35, 36, 42.

Rubus bartonianus

Rubus pensilvanicus

Phenology Flowering Mar–May. Flowering May–Jul.
Habitat Dry, rocky slopes Woodlands, savannas, prairies, fields, meadows, swamps, rock outcrops, sand dunes, sandy soil, disturbed areas, dry to wet soil
Elevation 300–400 m [1000–1300 ft] 0–1400 m [0–4600 ft]
Distribution
from FNA
ID; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; NB; NF; NS; ON; PE; QC [Introduced in Pacific Islands (Hawaii)]
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Rubus bartonianus is distinguished from the other flowering raspberries within its geographic range by its erect, unarmed stems, relatively small, simple leaves with acute to obtuse lobes, deeply cordate bases, sparsely hairy or glabrous abaxial surfaces, relatively large flowers with white petals, and densely long-hairy, clavate styles. The leaves superficially resemble those of Acer glabrum or some species of Ribes.

Rubus bartonianus is most similar to R. neomexicanus but especially R. deliciosus. The species is known only from the Snake River Canyon of Idaho and Oregon.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

As circumscribed here, Rubus pensilvanicus represents sect. Arguti (L. H. Bailey) L. H. Bailey, in which Bailey (1941–1945) recognized 109 species.

More strongly glandular plants of Rubus pensilvanicus may represent introgression with R. allegheniensis or other species, especially when exhibiting long-stipitate glands. Thyrsiform inflorescences are present in plants that have been called R. missouricus. There are reports (T. S. Mallah 1954; L. V. Clark and M. Jasieniuk 2012; B. Sutherland and L. A. Alice, unpubl.) of R. pensilvanicus hybridizing with R. ursinus.

Rubus pensilvanicus is introduced in California, Idaho, and Washington.

The following nothospecies names are based on putative hybrids involving Rubus pensilvanicus and: R. allegheniensis (R. ×avipes L. H. Bailey, R. ×floricomus Blanchard, R. ×orarius Blanchard); R. canadensis (R. ×amabilis Blanchard [not Focke], R. ×amicalis Blanchard, R. ×elegantulus Blanchard [=R. canadensis var. elegantulus (Blanchard) Farwell], R. ×multilicius L. H. Bailey, R. ×noveboracus L. H. Bailey, R. ×pergratus Blanchard [= R. canadensis var. pergratus (Blanchard) L. H. Bailey], R. ×crux Ashe); R. cuneifolius (R. ×acer L. H. Bailey, R. ×acer var. subacer L. H. Bailey, R. ×argutinus L. H. Bailey, R. ×floridensis L. H. Bailey); R. flagellaris (R. ×akermanii Fernald, R. ×darlingtonii L. H. Bailey, R. ×dissitiflorus Fernald, R. ×hypolasius Fernald, R. ×janssonii L. H. Bailey, R. ×largus L. H. Bailey, R. ×recurvicaulis Blanchard, R. rossbergianus Blanchard); R. setosus (R. ×wisconsinensis L. H. Bailey).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 9, p. 36. FNA vol. 9, p. 50.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus
Sibling taxa
R. allegheniensis, R. arcticus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parviflorus, R. parvifolius, R. pascuus, R. pedatus, R. pensilvanicus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. trivialis, R. ulmifolius, R. ursinus, R. vestitus
R. allegheniensis, R. arcticus, R. bartonianus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parviflorus, R. parvifolius, R. pascuus, R. pedatus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. trivialis, R. ulmifolius, R. ursinus, R. vestitus
Synonyms R. abactus, R. ablatus, R. abundiflorus, R. amnicola, R. andrewsianus, R. argutus, R. arvensis, R. associus, R. barbarus, R. bellobatus, R. betulifolius, R. blakei, R. bractealis, R. brainerdii, R. burnhamii, R. bushii, R. cardianus, R. condensiflorus, R. congruus, R. cupressorum, R. defectionis, R. densipubens, R. densissimus, R. facetus, R. fatuus, R. floridus, R. frondosus, R. gnarus, R. heterophyllus, R. humilior, R. impar, R. independens, R. insons, R. insulanus, R. interioris, R. jennisonii, R. jugosus, R. kelloggii, R. latifoliolus, R. laudatus, R. leggii, R. libratus, R. louisianus, R. missouricus, R. mollior, R. multispinus, R. oklahomus, R. originalis, R. paludivagus, R. pauper, R. pauxillus, R. penetrans, R. perfoliosus, R. perpauper, R. persistens, R. philadelphicus, R. praepes, R. pratensis, R. prestonensis, R. pubifolius, R. recurvans, R. saepescandens, R. sativus, R. subsolanus, R. subtractus, R. suus, R. tygartensis, R. ucetanus, R. virilis, R. vixargutus, R. wahlii, R. wiegandii
Name authority M. Peck: Rhodora 36: 267. (1934) Poiret: in J. Lamarck et al., Encycl. 6: 246. (1804)
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