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BC Conservation Data Centre: Species Summary


Fissidens pauperculus
poor pocket moss

 
Scientific Name: Fissidens pauperculus Howe
English Name: poor pocket 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: FISSPAU
Kingdom Phylum Class Order Family
Plantae Bryophyta Bryopsida Fissidentales Fissidentaceae
   
Conservation Status / Legal Designation
Global Status: G3? (May 2012)
Provincial Status: S1 (Apr 2024)
BC List: Red
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Endangered (Dec 2022)
SARA Schedule: 1  -  Endangered (Jun 2003)
General Status Canada:
   
Ecology & Life History
General Description:
Technical Description:
Identification Comments: Plants 1.5-2.5 mm tall, forming thin sods. Stems unbranched. Leaves in 3-5 pairs, pale green, not glossy, not much contorted when dry, 1.5-2.1 mm long, the tips acute to short acuminate, upper margins slightly toothed (crenulate to serrulate), indistinctly bordered with 1-2 rows of small short cells. Midrib (costa) ending 6-15 cells below the apex. Male and female sex organs on the same plant (autoicous). Stalks of capsule (setae) yellow when young, becomes reddish with age, 2-5 mm long. Capsules ovoid to oblong-ovoid, inclined to slightly bent. All members of the genus Fissidens are easily distinguished from other mosses by the paired leaves flattened in one plane along the stem, somewhat reminiscent of fern fronds, with the lower one-half to two-thirds of the blade folded to the base and Y-shaped in cross-section (Belland 2001b; Poor Pocket Moss Recovery Team 2007; Pursell 2007).
Similar Species: Fissidens aphelotaxifolius has been confused with F. pauperculus, but it differs from F. pauperculus in size, habitat, and presence of a distinct leaf margin. (Belland 2001b). Fissidens bryoides very closely resembles F. pauperculus in size and occurs in the same habitat, but its leaves are curled or crisped when dry, and the leaves have distinct borders of elongate cells.
Provincial Reproduction Comments: Detailed information on reproduction of Fissidens pauperculus is not available. As with all species of moss, sexual reproduction is by spores produced within a specialized structure called a sporangium. Fissidens pauperculus has male and female sex organs on the same plant, and at the single BC site it produces spores regularly. Capsules were present at five of the six observations made at Lynn Canyon. Asexual reproduction, if present, is considered to be important only for local dispersal and establishment. It is well known that many moss species reproduce asexually from broken leaf fragments or other plant parts, as well as from specialized propagules such as gemmae or deciduous leaves. Although not documented, it is likely that F. pauperculus could possess some means of asexual reproduction from plant fragments (Poor Pocket Moss Recovery Team 2007).
Provincial Ecology Comments: There is no specific information on the ecology of Fissidens pauperculus. In BC and elsewhere, it is restricted to exposed soil on banks of streams that are subject to erosion by seasonal high water. It requires bare soil and cannot compete with encroaching vegetation, although low light levels are not a limiting factor. Small stature and abundant spore production are indicative of is ability to rapidly colonize temporary habitats (Poor Pocket Moss Recovery Team 2007; J. Christy, pers. comm. 2008).
Habitats:
(Type / Subtype / Dependence)
Global Habitat Comments: On bare, moist soil banks, often growing with Fissidens bryoides (Lawton 1971).
Provincial Habitat Comments: There are no detailed published accounts of habitat for Fissidens pauperculus in BC. Schofield (1968) and Krause and Schofield (1977) described habitat in Lynn Canyon as "silty outcrop in seasonal streamlet," and "seepy consolidated silt cliff." Herbarium labels include "silt of damp slope" and "silt outcrop on canyon slope." Based on field work in 1999-2000, Belland (2001b) described habitat as an intermittently wet, silty outcrop along a streamlet in a mature Douglas-fir/western hemlock forest. The substrate is mostly dry in summer but wet in winter (Belland 2001b). All sites are shaded by trees with only intermittent sunshine later in the day. Suitable habitat can be generally described as seasonally moist, hard-packed silt-rich soils on steep faces in heavily shaded forested habitats within the CWHdm (Coastal Western Hemlock dry maritime) biogeoclimatic subzone. Associated bryophytes at Lynn Canyon include Dichodontium pellucidum and Jungermannia sp. (Poor Pocket Moss Recovery Team 2007).
Provincial Phenology:
(1st half of month/
2nd half of month)
Provincial Phenology Comments: Specific information on phenology of Fissidens pauperculus in BC is not available. As a general pattern, mosses in the Mediterranean climate favoured by this species are fertilized during fall rains and produce sprorophytes in the spring and summer. Spores are shed during summer and fall and germinate in the fall and winter. Photosynthesis and vegetative growth can occur throughout the winter in mild maritime climates, but these processes usually cease and plants go dormant during summer drought. "Flowering" in mosses would correspond to maturation of sex organs and the onset of fertilization (J. Christy, pers. comm 2008).
Elevation (m) (min / max): Provincial:  100 / 100
Known Pests:
Pollen Vector:
Pollinator:
Dispersal:
   
 
Provincial Inventory
Inventory Priority: B - Strong
Ownership of occurrences (Known locations): Mostly local government
Inventory Need: Inventory is needed to determine the full extent of the population at Lynn Canyon. Suitable riparian habitat in adjoining drainages such as Capilano Canyon in North Vancouver should be checked, as well as drainages south of the Fraser River south to the Washington border (Poor Pocket Moss Recovery Team 2007).
Inventory Comments: There is confusion about the exact locations of various populations of Fissidens pauperculus that have been reported over the years, and none have been permanently marked to date. W.B. Schofield visited the Lynn Canyon site at least seven times since its discovery in 1961, most recently in 2003, and he found this species each time in the same general location but at different microsites. He observed two patches: one plus or minus 625 square cm patch seen in 2000, and a smaller patch less than 2 m from the larger patch that he has seen occasionally since 1961. T. McIntosh has visited the site five times since 2003, first with W.B. Schofield, once in 2004, and three times in 2005. He observed two patches in 2003 (probably the same two reported by Schofield), none in 2005 following a severe rain, and six in a second 2005 visit. The latter six patches ranged from 1-40 square cm. Park rangers are looking for more suitable habitat in the area. A large bank of similar mineral composition about 20 m to the east was investigated for this moss on separate occasions by T. McIntosh and W.B. Schofield, but as of July 2005, none had been found there (T. McIntosh, pers. comm. 2007; Poor Pocket Moss Recovery Team 2007).
 
Economic Attributes
Provincial Economic Comments: No commercial or cultural uses are known for Fissidens pauperculus.
 
Distribution
Endemic: N
Global Range Comment: Endemic to North America. Known from British Columbia, Washington, and California (Lawton 1971). Also from northern Oregon (Schofield 1968).
Disjunct, more common elsewhere: N
Peripheral, major distribution elsewhere: Y
 
Authors / Contributors
Global Information Author:
Last Updated:
Provincial Information Author: Christy, John A.
Last Updated: Dec 16, 2008
Last Literature Search:
   
References and Related Literature
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC.
Belland, R.J. 2001b. COSEWIC status report on the poor pocket moss Fissidens pauperculus in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. 15 pp.
Flora of North America Editorial Committee (FNA). 2007b. Flora of North America north of Mexico. Vol. 27. Bryophytes: Mosses, Part 1. Oxford University Press, New York. xxi + 713 pp.
Krause, G. &W.B. Schofield. 1977. The moss flora of Lynn Canyon Park, North Vancouver, British Columbia. Syesis 10:97-110.
Lawton, E. 1971. Moss Flora of the Pacific Northwest. The Hattori Botanical Laboratory, Nichinan, Miyazaki, Japan.
Poor Pocket Moss Recovery Team. 2007. Recovery strategy for the poor pocket moss (Fissidens pauperculus M. Howe) in British Columbia. Prepared for the BC Ministry of Environment, Victoria, BC. 16 pp.
Pursell, R.A. 2007. Fissidentaceae. Pp. 331-357 in: Flora of North America Editorial committee (eds.). Flora of North America North of Mexico. Vol. 27: Bryophyta, part 1. Oxford University Press, New York. 713 pp. Also available on the internet .
Schofield, W.B. 1968. Bryophytes of British Columbia: I. Mosses of particular interest. J. of the Hattori Bot. Lab. 31: 205-226.
 

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. Species Summary: Fissidens pauperculus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Sep 8, 2025).