BC Conservation Data Centre: Species Summary
Bartramia halleriana
Haller's apple moss
| Scientific Name: | Bartramia halleriana Hedw. | ||||||||||
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| English Name: | Haller's apple moss | ||||||||||
| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Anderson, L.E., H.A. Crum, and W.R. Buck. 1990. List of the mosses of North America north of Mexico. The Bryologist 93(4):448-499. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Bryophyte | ||||||||||
| Species Code: | BARTHAL | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G5 (Feb 2025) | ||||||||||
| Provincial Status: | S2S3 (Apr 2024) | ||||||||||
| BC List: | Blue | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Threatened (Nov 2011) | ||||||||||
| SARA Schedule: | 1 - Threatened (Jun 2003) | ||||||||||
| General Status Canada: | |||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Identification Comments: | Plants 4 - 10 (15) cm tall, in tufts, green to yellow or brownish green, sometimes branched. Stems round in cross-section and tomentose with brownish rhizoids below. Upper leaves 5 - 7 mm long, curled or crisped when dry, erect and spreading or sometimes subsecund when moist, linear from a more or less sheathing base; margins tapering gradually to the base without forming an expanded or sheathing base, mostly bistratose, often with double teeth, costa strong, excurrent, often toothed at back above. Leaf cells thick-walled, papillose-mamillose on both surfaces, narrowly rectangular at base of leaf, quadrate rectangular above, 6 - 10 micrometres wide in mid-leaf. Male and female reproductive structures are located on the same plant (autoicous or synoicous). Setae curved, 1.5 - 4 mm long. Capsules immersed among leaves, more or less globose, not or slightly asymmetrical, striate or ribbed when dry (Belland 2001; Griffin 2003). | ||||||||||
| Similar Species: | Bartramia halleriana is differentiated from the three other Bartramia species in BC by its only slightly zygomorphic (non-symmetrical) capsules that are hidden among the leaves (immersed). The capsules are on very short setae (stalks) and appear nearly sessile. The common and widespread B. pomiformis closely resembles B. halleriana, grows in similar habitats, and identity of the two species has often been confused. In B. pomiformis, the capsules are distinctly zygomorphic and most are exserted on long setae well above the leaves (Belland 2001). | ||||||||||
| Provincial Reproduction Comments: | No specific information on reproduction is available for Bartramia halleriana. As with all mosses, sexual reproduction is by spores that are the primary means of dispersal and establishment in new areas. The male and female reproductive structures of B. halleriana are on the same plant, ensuring a high potential for fertilization and production of sporangia and spores. Bartramia halleriana produces spores at all known localities and would be expected to occur at many suitable sites. Near Mt. Robson, B. halleriana has been found with sporophytes every time the site was visited between 1955 and 1999, and most other known populations were also found with sporophytes. Despite ample spore production, populations remain rare. No accounts of asexual reproduction in B. halleriana have been published. Many species of moss produce specialized gemmae or deciduous leaves to facilitate vegetative propagation, but B. halleriana does not have any of these. Most species of moss also reproduce vegetatively by fragmentation, and B. halleriana presumably does also, although no specific studies are available. Factors limiting reproduction in B. halleriana are unknown, but competition from B. pomiformis may be instrumental in some habitats (Belland 2001). | ||||||||||
| Provincial Ecology Comments: | Information on the ecology of Bartramia halleriana is not available. Flowers (1935) noted its proclivity to avoid calcareous habitats, and all BC populations occur on silicaceous (acidic) rock types. Competition from Bartramia pomiformis may be a limiting factor (Belland 2001). | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
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| Global Habitat Comments: | In North America, Bartramia halleriana occurs in the "crevices of shaded cliffs, rock outcrops in humid forests" (FNA 2014). In Canada, this species is restricted to non-calcareous cliffs in low-elevation forests with a humidity source (occurring near falls, rapids, or seeps) (COSEWIC 2011). | ||||||||||
| Provincial Habitat Comments: | No detailed descriptions of habitat for Bartramia halleriana have been published for any part of its world range (Belland 2001). Flowers (1935) indicated that it does not occur in calcareous areas. Its habitat in BC is shaded, often north-facing, damp siliceous cliffs and talus slopes in the interior wet-belt cedar-hemlock (ICH) and Engelmann spruce-subalpine fir (ESSF) biogeoclimatic subzones in the Columbia and Rocky mountains. Associated vegetation includes Abies lasiocarpa, Alnus rubra, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii, Thuja plicata, and Tsuga heterophylla, with an understory of Menziesia ferruginea, Oplopanax horridus, Rubus parviflorus, Rubus pedatus, Vaccinium membranaceum, Vaccinium ovalifolium, Athyrium filix-femina, Clintonia uniflora, Cornus canadensis, Gymnocarpium dryopteris, Dryopteris expansa, Linnaea borealis, Lycopodium annotinum, Moneses uniflora, Orthilia secunda, Phegopteris connectilis, Tiarella unifoliata, Bartramia pomiformis, Hylocomium splendens, Metaneckera menziezii, Plagiopus oederiana, Pleurozium schreberi, Ptilium crista-castrensis, and Rhytidiadelphus triquestris. Habitat at Jasper National Park in Alberta is similar to those in BC but includes Picea mariana and Populus sp. (Belland 2001). | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
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| Provincial Phenology Comments: | Specific information on phenology of Bartramia halleriana in BC is not available. As a general pattern, most mosses in BC are fertilized in late summer to spring, and produce sprorophytes in spring to summer. Spores are shed during summer and fall and germinate from fall to spring. Photosynthesis and vegetative growth can occur throughout the winter in mild maritime climates, but in cold continental habitats such as those for B. halleriana plants are probably dormant during winter. "Flowering" in mosses would correspond to maturation of sex organs and the onset of fertilization. | ||||||||||
| Elevation (m) (min / max): | Provincial: 590 / 1170 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | B - Strong | ||||||||||
| Ownership of occurrences (Known locations): | Mixed private/government | ||||||||||
| Inventory Need: | Additional inventory for Bartramia halleriana is needed to determine the extent and viability of populations and other potential habitat that may be present near known sites and elsewhere in the Rocky Mountain area of BC. A population near Mt. Robson, first discovered in 1955, was still robust in 1999. A population found near Avola in 1995 could not be relocated in 2001 or 2005 despite thorough searches. Field work by Peter Achuff in 2004-2005 located seven new occurrences. More time and resources are needed for further work on this rare species. | ||||||||||
| Inventory Comments: | In North America, Bartramia halleriana occurs only in the Rocky Mountains of British Columbia and Alberta, where it is currently known from 9 occurrences or populations. Populations near Avola along the North Thompson River have not been seen since 1995 despite recent searches. It is possible that in the past the species was not well collected because of confusion with other species of Bartramia, but in recent searches by experts it is unlikely that the species was mistaken for the most common 'look-alike', B. pomiformis. Bartramia halleriana appears to be a truly rare species in BC and elsewhere in North America (Belland 2001). | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | No commercial or cultural uses are known for Bartramia halleriana. | ||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | Bartramia halleriana is a widespread species, occurring in Alberta and British Columbia, Canada, southern South America, Europe, Asia, the Pacific Islands (Hawaii, New Zealand), and Australia (Tasmania) (FNA 2014). In Canada, it occurs in Jasper National Park, Alberta and British Columbia along the Rocky Mountain Trench (COSEWIC 2011). Range extent was estimated using herbarium specimens and NatureServe Network occurrence data collected between 1994 and 2025 (Consortium of Bryophyte Herbaria 2025, GBIF 2025, NatureServe 2025). | ||||||||||
| Disjunct, more common elsewhere: | Y | ||||||||||
| Peripheral, major distribution elsewhere: | N | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | N. Ventrella (2025) | ||||||||||
| Last Updated: | Feb 04, 2025 | ||||||||||
| Provincial Information Author: | Christy, John A. | ||||||||||
| Last Updated: | Mar 18, 2008 | ||||||||||
| Last Literature Search: | |||||||||||
| References and Related Literature | |||||||||||
Anderson, L.E., H.A. Crum and W.R. Buck. 1990. List of the mosses of North America north of Mexico. Bryologist: 93(4) 448-499. |
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B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC. |
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Belland, R. 2001. COSEWIC status report on Haller's Apple Moss Bartramia halleriana in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. 1-17 pp. |
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Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2011. COSEWIC assessment and status report on the Haller's Apple Moss Bartramia halleriana in Canada. Ottawa. xi + 23 pp. Online. Available: www.registrelep-sararegistry.gc.ca/default_e.cfm (accessed 2025). |
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Flora of North America Editorial Committee (FNA). 2014a. Flora of North America north of Mexico. Vol. 28. Bryophytes: Mosses, part 2. Oxford Univ. Press, New York. vii + 702 pp. |
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Flowers, S. 1935. Bartramiaceae. Pages 152-180 in A.J. Grout. Moss flora of North America north of Mexico. Volume 2, part 3. Published by the author. Newfane, Vermont. 210 pp. |
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Griffin, D. 2003. Bartramiaceae. In Bryophyte flora of North America, provisional publication. Missouri Botanical Garden. Available online <http://www.mobot.org/plantscience/bfna/v2/BartBartramiaceae.htm>. |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. 2025. Species Summary: Bartramia halleriana. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 19, 2026).