OregonFlora: Vaccinium cespitosum vs. Vaccinium caespitosum

	Vaccinium cespitosum	Vaccinium caespitosum
		dwarf bilberry
Habit		Shrubs deciduous, up to 6 dm; twigs yellow-green to reddish, round in cross section to angled, glabrous to puberulent; rhizomatous.
Leaves		obovate to oblanceolate, 10–30 × 3–12 mm; thin; flexible, green abaxially; margins serrate on distal 25–50%, prominently reticulate-veined; tips rounded, sometimes subacute; surfaces abaxially glabrous or glandular, adaxially glabrous.
Inflorescences		solitary flowers in axils.
Flowers		sepals 5, light green; calyx lobes vestigial; petals 5; corollas cylindric-urceolate to globose, 4–6 × 3–5 mm, white to pink, glaucous; filaments > anthers, glabrous.
Fruits		5–8 mm in diameter, blue to bluish black, with a bloom.
2n		=24.

	Vaccinium cespitosum	Vaccinium caespitosum
Distribution	[WildflowerSearch map]	[WildflowerSearch map] [BONAP county map]
Discussion		Wet meadows to rocky mountain slopes. Flowering Apr–Aug. 50–2800 m. BR, BW, Casc, CR, ECas, Est, WV. CA, ID, WA; north to AK, east to Newfoundland, south to Guatemala. Native. Morphologically, V. caespitosum is very similar to V. deliciosum, making identification of these species difficult, particularly at higher elevations where their ranges overlap. The chromosome numbers of V. caespitosum (2n=24) and V. deliciosum (2n=48) may indicate that V. deliciosum is an autopolyploid derivative of V. caespitosum.
Source		Flora of Oregon, volume 2, page 639 Stephen Meyers
Sibling taxa	V. caespitosum, V. corymbosum, V. deliciosum, V. macrocarpon, V. membranaceum, V. myrtillus, V. ovalifolium, V. ovatum, V. oxycoccos, V. parvifolium, V. scoparium, V. uliginosum	V. corymbosum, V. deliciosum, V. macrocarpon, V. membranaceum, V. myrtillus, V. ovalifolium, V. ovatum, V. oxycoccos, V. parvifolium, V. scoparium, V. uliginosum
Synonyms		Vaccinium caespitosum var. caespitosum
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Vaccinium cespitosum

Vaccinium caespitosum

dwarf bilberry

Habit

Shrubs deciduous, up to 6 dm; twigs yellow-green to reddish, round in cross section to angled, glabrous to puberulent; rhizomatous.

Leaves

obovate to oblanceolate, 10–30 × 3–12 mm; thin; flexible, green abaxially;

margins serrate on distal 25–50%, prominently reticulate-veined;

tips rounded, sometimes subacute;

surfaces abaxially glabrous or glandular, adaxially glabrous.

Inflorescences

solitary flowers in axils.

Flowers

sepals 5, light green;

calyx lobes vestigial;

petals 5;

corollas cylindric-urceolate to globose, 4–6 × 3–5 mm, white to pink, glaucous;

filaments > anthers, glabrous.

Fruits

5–8 mm in diameter, blue to bluish black, with a bloom.

=24.

Vaccinium cespitosum

Vaccinium caespitosum

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Wet meadows to rocky mountain slopes. Flowering Apr–Aug. 50–2800 m. BR, BW, Casc, CR, ECas, Est, WV. CA, ID, WA; north to AK, east to Newfoundland, south to Guatemala. Native.

Morphologically, V. caespitosum is very similar to V. deliciosum, making identification of these species difficult, particularly at higher elevations where their ranges overlap. The chromosome numbers of V. caespitosum (2n=24) and V. deliciosum (2n=48) may indicate that V. deliciosum is an autopolyploid derivative of V. caespitosum.