The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Cusick's serviceberry, Cusick's shadbush, saskatoon

Habit Shrubs, 2–8 m. Stems 1–50, 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.

Inflorescences

(4–)6–8(–10)-flowered, (17–)26–36(–47) mm.

Pedicels

(0 or)1 or 2 subtended by a leaf, proximalmost (4–)9–14(–18) 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).

Pomes

bluish black, 10 mm diam. 2n = 4x.

Amelanchier cusickii

Phenology Flowering Mar–Jul; fruiting May–Aug.
Habitat Basaltic ledges, cliffs, and bluffs along streams, stony soil, streambeds, stream banks, copses, mountainsides, roadsides
Elevation 600–2300 m (2000–7500 ft)
Distribution
from FNA
ID; MT; OR; WA; BC
[BONAP county map]
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.)

Source FNA vol. 9, p. 652.
Parent taxa Rosaceae > subfam. Amygdaloideae > tribe Maleae > Amelanchier
Sibling taxa
A. alnifolia, A. amabilis, A. arborea, A. bartramiana, A. canadensis, A. fernaldii, A. gaspensis, A. humilis, A. interior, A. intermedia, A. laevis, A. nantucketensis, A. nitens, A. pallida, A. sanguinea, A. spicata, A. utahensis
Synonyms A. alnifolia var. cusickii, A. basalticola
Name authority Fernald: Erythea 7: 121. (1899)
Web links