Site menu:

Also see

Other crowberries:   E. eamesii
  E. nigrum

Ericaceae: Corema conradii (Torr.) Torr. ex Loud.
(broom crowberry)

Corema conradii is one of three crowberries in Nova Scotia; others are Empetrum nigrum (black crowberry) and Empetrum eamesii (rockberry).1 They are low evergreen shrubs with small, needle-like ericoid leaves and reduced, wind-pollinated flowers. C. conradii has an erect, candleabra- or broom-like growth form, reaching 15-50 cm height. C. conradii is dioecious with terminal flowers appearing in late April/May. The species is abundant in open pine barrens in Nova Scotia (often associated with bearberry) and on somewhat exposed rock ledges and gravelly areas near the coasts. It is not recorded for Cape Breton. Martine et al.2 comment that “ throughout its range, C. conradii primarily occurs in habitats historically prone to fire”. C. conradii is a member of the Atlantic Coastal Plain Flora. It occurs in small disjunct populations on the Atlantic coast from Nova Scotia to New Jersey. Reports of C. conradii occurring in Newfoundland are apparently erroneous.3 Populations in Nova Scotia are cited as secure (S4). In contrast, it was either never present or is extirpated in New Brunswick4, imperilled (S2) in the Magdallen Islands of Quebec and in P.E.I. , has S3S4 status in Maine and S1 (at risk) to S3 (sensitive) status for other U.S. states where it occurs (Massachusetts, New Jersey, New York). However, threats to C. conradii habitats cited by the Center for Plant Conservation in the U.S. apply also to Nova Scotian habitats. These include shoreline erosion, deer browsing, trampling, fire suppression, development.5 and invasion by Scot's Pine.6 The Annapolis heathlands, dominated by C. conradii, have been reduced to less than 3% of their pre-colonial area (approx. 200 km2).7
Sources | Notes & Refs | Selected Web Resources | Line Drawing

Click on images for larger versions.


February 11, 2007. Halifax Co., upland barrens near West Dover.
Photographer: JackPine.
Corema conradii, broom crowberry Corema conradii, broom crowberry

March 25, 2006. Halifax County: Purcells Cove area, upland barrens.
Photographer: JackPine.
Corema conradii, broom crowberry

Flower buds. Bar is 1 cm.


April 23, 2006. Halifax County: Purcells Cove area, upland barrens.
Photographer: JackPine.
Corema conradii, broom crowberry

Female (foreground) and
male (background) plants.

Corema conradii

Female (left) and male plants. Bar is 5 cm.


April 30, 2009. Halifax County: Bluff Wilderness Hiking Trail (near Hubley)
Photographer: JackPine.
Corema conradii

Habit and habitat: thick busy colonies, lichens largely excluded.

Corema conradii

Habitat (March 21): patches of broom croberry and reindeer lichen on the more exposed areas.

Corema conradii At left:
Female plants in foreground, male plants behind. Fielding describes males as presenting "a haze of
wine-coloured anthers".8
Corema conradii

Male plants

Corema conradii

Patch of female plants; male plants in background.

Corema conradii

Close-up of female flower.

Corema conradii

Close-up of male flower.


May 4, 2008. Halifax County: Captain Arnell lands (off of Purcells Cove road).
Photographer: JackPine. Notes
Corema conradii

Habitat: jack pine barrens

Corema conradii

Female flowers

Corema conradii

Male flowers.

Corema conradii

June 7, 2009. Halifax County: The Bluff Wilderness Hiking Trail, Pot Lake Loop.
Photographer: JackPine.
Corema conradii

Fruits. Scale is 5 mm,

Corema conradii
Corema conradii

Male flowers (spent),


July 11 & 14, 2009. Halifax County barrens.
Photographer: JackPine.
Corema conradii: fruit with elaisomes Corema conradii: fruit with elaisomes

Above and left: Plants on granite outcrop above Oceanview Drive, Halifax manland south, July 11. Bar is 5 mm. Below, plants on barrens of the Bluff Wilderness Hiking Trail., July 14. At both locales, elaisomes9 were observed on fruits (as shown in the photos) and fruits were fully mature, dropping off when plants were disturbed slightly.

Corema conradii: fruit with elaisomes Corema conradii: fruit with elaisomes

Aug 3-4, 2008. Shelburne County: Indian Fields pine barrens.
Photographer: JackPine. Notes
Corema conradii

Habitat: sand barrens

Cirema conradii
Corema conradii

Junction with bearberry (Arctostaphylos uva-ursi).

Corema conradii

With sweetfern (Comptonia peregrina).

Corema conradii


Corema conradii

C. conradii growing with Hudsonia ercoides between ATV wheel tracks.


Aug. 16, 2013. Kings County: Kingston
Photographer: JackPine.
Corema conradii, Nova Scotia

Corema conradii on remnant Annapolis heathland in the Kingston area. It grows in pure stands on thicker sand as above; in thin sand, it was mixed with bearberry (Arctostaphylos uva-ursi) and reindeer lichen as at right, & lowbush blueberry (Vaccinium angustifolia); large patches of Hudsonia ericoides were also seen at this site.

Corema conradii, Nova Scotia
Corema conradii, Nova Scotia
Panorama illustrates the interface between Annapolis pine barrens/heathland and residential development. A ball field lies in the background at left.
Corema conradii, Nova Scotia

broom crowberry in Nova ScotiaPhotos illustrate how a resident in the Kingston area integrated large patches of naturally occurring broom crowberry into a residential landscape. Top left: broom crowberry heath in centre; edges are mowed regularly (photo at left). Broom crowberry persists where it has been mowed.
Corema conradii, Nova Scotia
Corema conradii, Nova Scotia

Above: undisturbed pine barrens on the border of the residential landscape.


Aug. 18, 2005. Halifax County: Polly's Cove
Photographer: JackPine.
Corema conradii, broom crowberry

Granite barrens, Corema conradii..

Corema conradii, broom crowberry

E. nigrum on the same outcrop, in slight depression.

Corema conradii, broom crowberry

Corema conradii
left; E. nigrum, right.

Distinguishing C. conradii from E. nigrum can sometimes be challenging when there are no reproductive structures present, especially on drier sites such as this one where E. nigrum takes on a more branched, ascending growth form similar to that of C. conradii. See Three Crowberries for further comments.

Sep. 16, 2006. Halifax County: Polly's Cove
Photographer: JackPine.
Corema conradii Corema conradii

Habitat: granite barrens. C. conradii forms a patch around a small white pine; bearberry (Arctostaphylos uva-ursi) in the foreground, Junper commune and huckleberry (Gaylussacia baccata) in background.


Dec. 2, 2008. Halifax County: Herring Cove Road, close to York Redoubt.
Photographer: JackPine.
Corema conradii, broom crowberry Corema conradii, broom crowberry

Left: Twigs. Bar is 5 mm.
Above: Leaves. Bar is 2 mm.
See also Three Crowberries

Corema conradii, broom crowberry

Habitat: Large granite outcrops & erratics

.
Corema conradii, broom crowberry

With reindeer lichen

.
Corema conradii, broom crowberry

No lichens.

Corema conradii, broom crowberry

Mat pulled back.

Corema conradii, broom crowberry

No flower buds.

Corema conradii, broom crowberry

Many flower buds.

Corema conradii, broom crowberry

Bar is 2 mm.


Post-fire photos

May 4, 2009. Halifax County: Herring Cove backlands (Purcells Cove Road).
Photographer: JackPine.
Corema conradii after a severe fire C. conradii: a fire prone/fire adapted species.

On April 30, 2009, a restricted but severe forest fire on the south mainland region of Halifax burned over barrens that supported large populations of Corema conradii. These photos were taken a few days later.

As noted in the introduction, fire supression is a factor reducing populations of C. conradi i. Martine et al.2 reported that “a hot fire burned through one of the most extensive New Jersey populations of this state-endangered species during the summer of 2001, resulting in mortality of nearly all plants in the burned areas. Significant seedling recruitment occurred in the fall of 2002, followed by an even greater seedling emergence the following year.” It appears that established plants were likewise completely destroyed in burned areas of the May 4 Halifax fire.

This area has many mature jack pines, an indicator of a fire-dependent plant community. A local resident said that a fire went through the area when he was 5 years old, 44 years ago.
Corema conradii before a severe fire

Barrens overlooking Lower Mud Pond on November 9, 2005. Isolated colonies of Corema conradii mixed with lichens occur on the more exposed areas, and fringes of C. conradii at edges of outcrop by huckleberry (fire engine red) growing where there is some soil. Note jackpine at right.

Corema conradii after a severe fire

The same scene as at left, on May 4, 2009 after the fire. Lichen mats, C. conradii and huckleberry appeared to be completely destroyed.
 
 
 

Corema conradii after a severe fire Corema conradii after a severe fire

Left photo: in foreground, burned patch of huckleberry and C. conradii; in the background, C. conradii and lichens on top of a large erratic escaped obvious damage (closer view above).

soil

There was only superficial burning of the peaty soil, thus the buried seedbank may be largely intact.


Aug. 27, 2010. Halifax County: Herring Cove backlands, between Lower Mud Pond & East Pine Island Pond
Photographer: JackPine.
Corema conradii (broom crowberry) after fire Corema conradii (broom crowberry) after fire

Left: exposed rhizomes of C. conradii. Above: a patch with seedlings of C. conradii. Seedlings were not observed on a visit to this area on July 31, 2010. First appearance of seedlings in the late summer of the year after that of the fire is consistent with observations in New Jersey by Martine et al.2

Corema conradii (broom crowberry) after fire

A patch with numerous seedlings. Seedlings were not observed in most of the areas previously occupied by C. conradii.

Corema conradii (broom crowberry) after fire

Extracted plants from the patch at left confirm they are seedlings, not regrowth from rhizomes. Lines are 7 mm apart.


Selected Web Resources


Notes & References

  1. A recent revison of the Ericaceae places the crowberries, formerly inlcuded in the family Empetraceae, in the family Ericaeae. subfamily Ericoideae, tribe Empetrea. See Kron, K.A. et al. 1992. Phylogenetic classification of Ericaceae: molecular and morphological evidence. The Botanical Review 68(3): 335-423.
  2. Martine, C.T., Lubertazzi,D. & Dubrul, A. 2005. The biology of Corema conradii: natural history, reproduction, and observations of a post-fire seedling recruitment. Northeastern Naturalist 12(3):267-286.
  3. Maunder, J. and others. A Digital Natural History of Newfoundland and Labrador (www.digitalnaturalhistory.com/) Appendix 1: Species Excluded from the Provincial Flora. Posted at http://digitalnaturalhistory.com/Appendix_1_nfinal.rtf
  4. Hinds, H.R. 2000. Flora of New Brunswick, 2nd ed. Biology Department, University of New Brunswick.
  5. CPC National Collection Plant Profile (online): Corema conradii Accessed 25 Nov. 2008 at http://www.centerforplantconservation.org/
  6. Catling, P. M., and S. Carbyn. 2004. Invasive Scots Pine (Pinus sylvestris) replacing Corema heathland in the Annapolis valley. Canadian Field-Naturalist 19(2): 237-244.
  7. Carbyn. S., P. M. Catling, S. P. Vander Kloet. and S. Ba.squill. An analysis of the vascular flora of Annapolis Heathlands, Nova Scotia. Canadian Field-Naturalist 120(3): 351-362.
  8. Fielding, R.R. 1998. Shrubs of Nova Scotia. Halifax: Nimbus Publishing and N.S. Department of Natural Resources.
  9. Thanks to Nick Hill for suggesting that I look out for these structures in mature fruits. Elaisomes are fleshy structures attached to seeds or fruits that facilitate dispersal of seeds by ants. "This dispersal syndrome, usually termed myrmecochory, involves the diaspores being caried away from the parent plants, often to or near the ant nest, where the ants feed upon the fat- and protein-rich elaiosomes while leaving the seeds intact.. Myrmecochory is believed to occur in plant species belonging to at least 67 plant families and is particularly common in forest herbs of eastem North America and the sclerophyil vegetation of South Africa and Australia. (Source: Pemberton, R.W. & and Irving, D.W. 1990. Elaiosomes on weed seeds and the potential for myrmecochory in naturalized plants. Weed Science38: 615-619.) From Martine et al. 2: "The fruits of C. conradii are unlike those produced by its only congener. Corema album (L.) D. Don (Empetraceae), an endangered endemic of the west coast of the Iberian Peninsula (Calvino-Cancela 2002, Diaz Barradas et al. 2000. Guitian et al. 1997), in that they are not only "scarcely larger than a pin-head" (Mathews 1915) but devoid of the fleshiness associated with bird dispersal. The fruits do bear elaisomes (fleshy or oily appendages typically associated with ant dispersal), however, and ants of the Aphaenogaster rudis Emery speeies complex have been observed in Nantucket, Massachusetts transporting, storing, and discarding C. conradii fruits (Dunwiddie 1990)."