The specific name cespitosum means forming tufts and is probably in reference to the way this species creates dense patches. Dwarf blueberry is a very widespread species, occurring as far away as the highlands of Guatemala, but it is very rare in New York.
There are two known populations. One of these populations has only one individual while the other has a few hundred. There are also four historical populations which have not been seen for over 40 years. Some of these historical populations have been looked for but more survey work is needed to determine if they have become extirpated.
Short-term trends are unclear but one of the extant sites has only one plant. This may indicate that a new population has begun or that an old population is declining.
Four populations have not been seen in over 40 years. Some of these populations have been searched for but more survey work is needed to determine if they are truly extirpated. No other data on long-term trends exists.
At one of the extant populations, the plants grow along the edges of a trail. Although trampling by hiker traffic at this site does not currently appear to be a problem, it is a potential threat.
Protect the one population that is close to a trail from being damaged by trampling by hiker traffic. The Summit Steward program which works to inform hikers of the fragile nature of alpine plants is a critical program which is helping to reduce trampling of alpine vegetation. This program and other efforts designed to reduce trampling of alpine meadows are needed.
Specimens which document the historical populations from Oneida and Warren counties need to be verified. All historical populations need to be thoroughly sought. The two known populations need to be surveyed regularly and clear, consistent estimates of population size need to be made. Research should be conducted on how to help the population with only one individual to persist and spread.
In New York, Vaccinium cespitosum occurs along the banks of large rivers, at rocky stream banks in high elevation fir dominated forests, and in openings in krummholz, but primarily in alpine meadows. It is known from along the edges of trails in moss (New York Natural Heritage Program 2007). "Dry or wet acidic sites from sea level to 4500 meters. In mountainous regions, it has been found along crater rims, in volcanic ash, talus slopes, rocky ledges, alpine sedge meadows, edges of valley glaciers, alpine herb mats, edges of coniferous forests, subalpine heaths, and open pine woods. Elsewhere it has been found along rocky or sandy lake shores; rocky, gravelly, or sandy river banks; gravel terraces, headlands, low arctic tundra, jack pine outcroppings, open spruce woods, barrens, dry oak woods, dry pine woods, poplar regeneration forests, road cuts, and railway rights-of-way" (Vander Kloet 1999). In Maine, it occurs on gravelly or rocky shores and clearings, and is casually alpine (Haines 1998).
Currently, in New York this species is known only from the high peaks region of the Adirondacks. There are two historical records which need to be verified from the southern parts of northern New York .
It occurs from Alaska to Newfoundland, south to southern Maine, southern Vermont, northern New York, Michigan, and in the west, south to the western highlands of Guatemala (Voss 1996, Vander Kloet and Dickinson 1999, New York Natural Heritage Program 2007).
Dwarf blueberry is a low shrub (up to about 8 to 12 inches tall) that forms dense patches. Its twigs are ridged and usually minutely hairy with scattered, white, downward-hooked hairs. The shining leaves are about 1/2 to 1 and 1/4 inches long and 1/8 to 1/2 inches wide. The margins have minute, glandular teeth at least in the upper half. The 5-lobed, nodding, white to usually pink flowers, are about 1/8 to 1/4 inches long, lantern-shaped, and solitary in the leaf axils. The fruits are light blue and have a very thin waxy coating (Fernald 1970, Gleason and Cronquist 1991, Vander Kloet and Dickinson 1999)
Vaccinium cespitosum is a dense often matted shrub that only gets to about 20 or at most 30 cm in height, although outside of northeastern North America it can grow up to 60 cm tall. Only two scales cover the buds. The twigs are not papillose. The leaves are oblanceolate to obovate, green, serrate on the upper half, and glabrous. The flowers are 5-merous, solitary in the leaf axils of the current season's branches, and have rounded low calyx lobes. A pair of upward projecting spurs (in addition to the terminal tubules) occurs on the anthers (Fernald 1970, Gleason and Cronquist 1991, Haines and Vining 1998, Vander Kloet and Dickinson 1999).
This species can be identified fairly easily when in flower or fruit, although the flowers are particularly helpful and collections should include them.
Vaccinium cespitosum is a very distinctive taxon in New York.
Vaccinium angustifolium and V. boreale can occur with V. cespitosum. The two former species are distinguished by elliptic leaves with acute apices, the flowers occurring in clusters, the calyx lobes evident and not rounded, the twigs papillose, and the anthers not spurred.
Vaccinium uliginosum also can occur with V. cespitosum. It differs in having flowers with four petals instead of five, more than two scales covering buds, leaves entire, densely hairy below, and blue-green, and flowers solitary or paired, arising from the previous year's branches (Voss 1996, Haines and Vining 1998). It is much more common in the alpine areas.
This species is in flower from late June through July. Therefore, the best time to survey for this species is during this time frame although it can be seen vegetatively all season.
The time of year you would expect to find Dwarf Bilberry vegetative, flowering, and fruiting in New York.
Vaccinium cespitosum Michaux
Vaccinium cespitosum is in section Myrtillus (Vander Kloet and Dickinson 1999). Camp (1942) recognized V. cespitosum as well as various other closely related species. Of these species, only V. cespitosum is known from New York. Kartesz (1994) lumped some of these species and recognized two varieties (var. cespitosum and var. paludicola) under V. cespitosum. Following the nomenclature of Kartesz, only var. cespitosum is known from New York. Further work on section Myrtillus by Vander Kloet and Dickinson (1999) also resulted in the lumping of many of the taxa Camp (1942) recognized and left V. cespitosum without any subspecific taxa. The specific epithet cespitosum was used in Michaux's (1803) original publication. Some authors (Camp 1942, Vander Kloet and Dickinson 1999) have altered the spelling to caespitosum but the original spelling needs to be followed (Greuter et al. 2000).
Haines, A. and T.F. Vining. 1998. Flora of Maine, A Manual for Identification of Native and Naturalized Vascular Plants of Maine. V.F.Thomas Co., Bar Harbor, Maine.
Camp, W.H. 1942. A survey of the American species of Vaccinium, subgenus Euvaccinium. Brittonia 4: 205-247.
Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.
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Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.
Kartesz, John T. 1994. A synonomized checklist of the vascular flora of the United States, Canada and Greenland. Volume 1-Checklist. Volume 2-Thesaurus.
New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.
New York Natural Heritage Program. 2020. New York Natural Heritage Program Databases. Albany, NY.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
Vander Kloet, S.P. and T.A. Dickinson. 1999. The taxonomy of Vaccinium section Myrtillus (Ericaceae). Brittonia 51: 231-254.
Voss, Edward G. 1996. Michigan Flora Part III. Dicots Concluded (Pyrolaceae - Compositae). Cranbrook Institute of Science Bulletin 61 and University of Michigan Herbarium. 622 pp.
Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York
Information for this guide was last updated on: December 30, 2008
Please cite this page as:
New York Natural Heritage Program. 2020. Online Conservation Guide for Vaccinium cespitosum. Available from: https://guides.nynhp.org/dwarf-bilberry/. Accessed November 25, 2020.