Amelanchier cusickii |
Amelanchier intermedia |
|
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Cusick's serviceberry, Cusick's shadbush, saskatoon |
amélanchier intermédiaire, intermediate serviceberry, intermediate shadbush |
|
Habit | Shrubs, 2–8 m. Stems 1–50, solitary or in colonies. | Shrubs or trees, 2–7 m. Stems 1–50, fastigiate, solitary or in colonies. |
Leaves | fully unfolded; petiole (9–)12.8–19(–28) mm; blade elliptic to suborbiculate, (22–)33–46(–61) × (13–)25–32(–50) mm, base subcordate to truncate, each margin with (0 or)1–6(–11) teeth on proximal 1/2 and (2–)4 or 5(–7) teeth in distalmost cm, largest teeth 1 mm, apex usually truncate, sometimes mucronate to acute, abaxial surface glabrous or sparsely hairy by flowering, glabrous (or sparsely hairy) later, adaxial glabrous later. |
half-unfolded; petiole (14–)16–21.8(–24) mm; blade elliptic to slightly obovate, (39–)46–65(–77) × (25–)26–38(–45) mm, base subcordate or rounded, each margin with (5–)13–19(–20) teeth on proximal 1/2 and (5–)13–19(–20) teeth in distalmost cm, largest teeth less than 1 mm, apex acute to short-acuminate, abaxial surface sparsely hairy by flowering, surfaces glabrous later. |
Inflorescences | (4–)6–8(–10)-flowered, (17–)26–36(–47) mm. |
(6 or)7–10-flowered, 35–59(–77) mm. |
Pedicels | (0 or)1 or 2 subtended by a leaf, proximalmost (4–)9–14(–18) mm. |
0 or 1 subtended by a leaf, proximalmost (13–)14–25(–33) mm. |
Flowers | sepals erect to recurved after flowering, (2.6–)3.3–4.3(–5.3) mm; petals obovate to oblanceolate, (10.8–)13.3–20.1(–23.2) × (2.3–)3.3–6.3(–7.5) mm; stamens (14–)18–20(–21); styles (4 or)5, (1.7–)2.6–4(–4.8) mm; ovary apex glabrous or sparsely hairy (or with a ring of hairs at base of styles). |
sepals ascending to recurved after flowering, (2–)3.3–4.5(–5.2) mm; petals oblong, (10–)12.7–17.7(–18.5) × (3–)3.9–5.3(–5.7) mm; stamens (18–)20(–21); styles (4 or)5, (3.3–)3.8–4.8(–5) mm; ovary apex glabrous (or sparsely hairy). |
Pomes | bluish black, 10 mm diam. 2n = 4x. |
dark purple, 7–12 mm diam. 2n = 4x. |
Amelanchier cusickii |
Amelanchier intermedia |
|
Phenology | Flowering Mar–Jul; fruiting May–Aug. | Flowering May–Jun; fruiting Jun–Aug. |
Habitat | Basaltic ledges, cliffs, and bluffs along streams, stony soil, streambeds, stream banks, copses, mountainsides, roadsides | Swamps, bogs, thickets, shores |
Elevation | 600–2300 m (2000–7500 ft) | 0–1000 m (0–3300 ft) |
Distribution |
ID; MT; OR; WA; BC |
CT; MD; ME; MI; MN; NC; NH; NJ; NY; PA; SC; VA; VT; NB; NF; NS; ON; PE; QC |
Discussion | Amelanchier cusickii has distinctively long petals. Leaves that are glabrous upon expanding and glabrous or sparsely hairy ovary apices are also useful for identification. The species flowers before A. alnifolia, which suggests that the two are genetically distinct. G. N. Jones (1946) noted that A. alnifolia and A. cusickii frequently grow together and that there is no evidence of hybridization; the authors have observed hybridization between A. alnifolia var. semiintegrifolia and A. cusickii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Amelanchier intermedia is morphologically closest to A. laevis. In a study of morphologic variation involving A. canadensis, A. intermedia, A. laevis, and other species of Amelanchier, A. C. Dibble et al. (1998) found that the only two species that overlap are A. intermedia and A. laevis. P. Landry (1975) considered A. intermedia to be the hybrid of A. arborea (including A. laevis) and A. canadensis, and the authors have data that suggest A. intermedia is a hybrid of A. canadensis and A. laevis. Amelanchier intermedia hybridizes with A. bartramiana, A. humilis, and A. spicata (L. Cinq-Mars 1971). A. C. Dibble et al. (1998) reported that two individuals of Amelanchier intermedia, both tetraploids, were apomictic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 652. | FNA vol. 9, p. 660. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Amelanchier | Rosaceae > subfam. Amygdaloideae > tribe Maleae > Amelanchier |
Sibling taxa | ||
Synonyms | A. alnifolia var. cusickii, A. basalticola | |
Name authority | Fernald: Erythea 7: 121. (1899) | Spach: Hist. Nat. Vég. 2: 85. (1834) |
Web links |