Draba glabella R. Mitchell

Draba glabella
R. Mitchell

Class
Dicotyledoneae (Dicots)
Family
Brassicaceae (Mustard Family)
State Protection
Endangered
Listed as Endangered by New York State: in imminent danger of extirpation in New York. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
S1
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
G5
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).

Summary

Did you know?

Whitlow grass was the European name given to several inconspicuous wildflowers such as Saxifraga tridactylites, Draba verna and Paronychia which were thought to be a cure for the Whitlow. This is an infection of the end of the fingers and toes around the nail, as well as the hooves of animals, which caused painful inflammation. The genus Draba is from the Greek "drabe" meaning sharp or acrid and refers to the burning taste of the leaves of these medicinal plants. In the northeastern states Draba glabella is critically imperiled, and known only from the shorelines of large lakes in New York, Vermont, and Maine

State Ranking Justification

There are only two verified and current locations, with one additional historical location recorded. There is plenty of apparently suitable habitat, and additional searching is warranted. This species is relatively inconspicuous and therefore may have been overlooked.

Short-term Trends

One of the two known existing populations has been surveyed only once. The other has persisted at the site for over 50 years, and has maintained its current size for the last 25 years.

Long-term Trends

With only one historical and two existing popuations known, this plant has likely always been rare in New York, but there are too few sites to assess long-term trends.

Conservation and Management

Threats

Herbivory, fire, and succession may threaten some locations.

Conservation Strategies and Management Practices

A buffer should be maintained around populations of this plant.

Research Needs

Research could help determine the reasons for the rarity of this species in New York and adjacent states.

Habitat

Habitat

In New York Draba glabella has been found only on limestone cliffs and woodland adjacent to Lake Champlain (New York Natural Heritage Program 2007). Rocky or gravelly places and cliff crevices (Gleason and Cronquist 1991).

Associated Ecological Communities

  • Calcareous cliff community (guide)
    A community that occurs on vertical exposures of resistant, calcareous bedrock (such as limestone or dolomite) or consolidated material; these cliffs often include ledges and small areas of talus.
  • Calcareous red cedar barrens* (guide)
    A small-patch calcareous rocky summit community occurring on dry, south-facing to southwest-facing slopes and low summits. These sites are characterized by stunted, sparse woodlands with small grassland openings. * probable association but not confirmed.
  • Calcareous shoreline outcrop* (guide)
    A community that occurs along the shores of lakes and streams on outcrops of calcareous rocks such as limestone and dolomite. The vegetation is sparse; most plants are rooted in rock crevices. * probable association but not confirmed.
  • Calcareous talus slope woodland* (guide)
    An open or closed canopy community that occurs on talus slopes composed of calcareous bedrock such as limestone or dolomite. The soils are usually moist and loamy; there may be numerous rock outcrops. * probable association but not confirmed.
  • Limestone woodland (guide)
    A woodland that occurs on shallow soils over limestone bedrock in non-alvar settings, and usually includes numerous rock outcrops. There are usually several codominant trees, although one species may become dominant in any one stand.
  • Northern white cedar rocky summit* (guide)
    A community that occurs on cool, dry, rocky ridgetops and summits where the bedrock is calcareous (such as limestone or dolomite), and the soils are more or less calcareous. The vegetation may be sparse or patchy, with numerous rock outcrops. The species have predominantly boreal distributions. * probable association but not confirmed.
  • Red cedar rocky summit* (guide)
    A community that occurs on warm, dry, rocky ridgetops and summits where the bedrock is calcareous (such as limestone or dolomite, but also marble, amphibolite, and calcsilicate rock), and the soils are more or less calcareous. The vegetation may be sparse or patchy, with numerous lichen covered rock outcrops. * probable association but not confirmed.
  • Successional red cedar woodland*
    A woodland community that commonly occurs on abandoned agricultural fields and pastures, usually at elevations less than 1000 ft (305 m). The dominant tree is eastern red cedar, which may occur widely spaced in young stands and may be rather dense in more mature stands. * probable association but not confirmed.

Associated Species

  • Aquilegia canadensis (wild columbine, red columbine)
  • Arabis x divaricarpa
  • Campanula rotundifolia (hare-bell)
  • Carex platyphylla (broad-leaved sedge)
  • Epilobium angustifolium
  • Melilotus albus (white sweet-clover)
  • Oryzopsis asperifolia (spreading white grass)
  • Ostrya virginiana (hop hornbeam, ironwood)
  • Thuja occidentalis (northern white cedar, arbor vitae)

Range

New York State Distribution

In New York Draba glabella is known only from only two locations along Lake Champlain, in Clinton and Washington counties.

Global Distribution

Draba glabella is known from Alaska and all of Canada except Saskatchewan, from Montana and Wyoming in the western U.S., and from Wisconsin and Michigan, east through Ontario, to New York, Vermont, and Maine.

Identification Comments

General Description

Draba glabella is a small (4 to 16 inches tall) herbaceous perennial, growing from a hardened base just underground (a caudex) to a basal rosette of hairy, 2.5 inch-long, often dentate leaves.. From the rosette grows a single stem with a few dentate leaves and a loose terminal raceme up to 4 inches long, bearing 4-petaled flowers, the petals are yellow in bud but white upon opening. These mature into a flattened, lance-shaped fruit called a silique. The fruit are flattened, glabrous, and about 1/4 to 1/2 inch long.

Identifying Characteristics

Draba arabisans is a sturdy perennial growing from a thick caudex, 1-4dm tall, with many basal but few cauline leaves, the basal leaves narrowly oblanceolate to spatulate, up to 6cm long, often sharply toothed, and stellate-hairy. The infloresence is a loose raceme up to 10 cm long, the pedicels without leaves or bracts, and glabrous or nearly so. The petals appear yellow in bud but are white after opening, and 4-6mm long. The persistent style is .3 to .8 mm long. The fruits are glabrous siliques, 7 -11 mm long and .25x to .4x as wide as long, straight or nearly so, and with the style .1 to .3mm long or virtually obsolete in depauperate specimens.

Best Life Stage for Proper Identification

Mature fruit is preferred in order to positively distinguish this species from the closely related Draba arabisans.

Similar Species

New York has 3 other species of Draba. D. verna, an exotic species, is an annual, more slender than D. arabisans, with deeply split petals. D. reptans is also a slender annual, with entire basal leaves 3 cm long or less, shorter than the sharply toothed basal leaves of D. glabella, which may reach 6cm. Both of these species are typically found in sandy or disturbed habitats. The only other perennial Draba in New York, which like D. glabella is found on cliffs and rocks, is Draba arabisans. Very similar to D. glabella, D. arabisans typically has fruits which are twisted at maturity, are .2x to .25x as wide as long, and have a style from .3 to .8mm long.

Best Time to See

Draba glabella flowers from late May until late June, with fruits visible approximately through the beginning of October. Individual plants may be found with flowers at the top of the infloresence and developing fruit below, which may be helpful in identification.

  • Flowering
  • Fruiting

The time of year you would expect to find Smooth Whitlow Grass flowering and fruiting in New York.

Smooth Whitlow Grass Images

Taxonomy

Smooth Whitlow Grass
Draba glabella Pursh

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Dicotyledoneae (Dicots)
        • Order Capparales
          • Family Brassicaceae (Mustard Family)

Additional Common Names

  • Smooth Draba

Synonyms

  • Draba laurentiana Fern.

Additional Resources

References

Allard, Dorothy J. 1993. Draba glabella Pursh. Smooth Whitlow-grass Conservation and Research Plan for New England. New England Wild Flower Society. Framingham, MA. 23 pp.

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.

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.

Mitchell, Richard S. and Gordon C. Tucker. 1997. Revised Checklist of New York State Plants. Contributions to a Flora of New York State. Checklist IV. Bulletin No. 490. New York State Museum. Albany, NY. 400 pp.

New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.

Voss, E.G. 1985. Michigan Flora. Part II. Dicots (Saururaceae - Cornaceae). Cranbrook Institute of Science and University of Michigan Herbarium. Ann Arbor, Michigan. 724 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

Links

About This Guide

Information for this guide was last updated on: January 5, 2009

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Draba glabella. Available from: https://guides.nynhp.org/smooth-whitlow-grass/. Accessed November 14, 2019.

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