Spoon-leaved moss (Bryoandersonia illecebra) COSEWIC assessment and status report: chapter 4

Distribution

Global range

Bryoandersonia illecebra is endemic to eastern North America, where it ranges widely but occurs most commonly in the south (Crum & Anderson 1981; Robinson 1962). It is distributed from southern Ontario to Connecticut, New York, Ohio, Indiana, Iowa, Florida, and Texas (Crum & Anderson 1981, Missouri Botanical Garden 2001, New York Botanical Garden 2001) (Figure 3). Historical collections of B. illecebra from Alaska and the Canadian Rocky Mountains (see ‘Collections Examined’) have been discounted by recent sources (e.g. Crum & Anderson 1981, New York Botanical Garden 2001, Robinson 1962).

Figure 3. Approximate global distribution of the eastern North American endemic moss Bryoandersonia illecebra (Crum & Anderson 1981, Missouri Botanical Garden 2001, New York Botanical Garden 2001) (gray shading).

Figure 3. Approximate global distribution of the eastern North American endemic moss Bryoandersonia illecebra

Canadian range

Despite relatively intensive bryological exploration (Figure 4), Bryoandersonia illecebra is known from only six to eight sites in southern. Nine contemporary collections (since 1970) are known, and bear specific co-ordinates: they were collected from Essex, Middlesex, Elgin and Welland Counties in the extreme southern part of Ontario (Figure 5).

Figure 4. Collecting locations (Ireland & Ley 1992) for four common moss species (Anomodon attenuatus[triangles]), Aulacomnium palustre ([circles]), Callicladium haldanianum ([stars]), and Climacium dendroides ([diamonds]), with which Bryoandersonia illecebra has been collected in southern Ontario, demonstrating dense collecting effort.

Figure 4. Collecting locations (Ireland & Ley 1992) for four common moss species (Anomodon attenuatus [triangles]), Aulacomnium palustre ([circles]), Callicladium haldanianum ([stars]), and Climacium dendroides ([diamonds]), with which Bryoandersonia illecebra has been collected in southern Ontario, demonstrating dense collecting effort

Figure 5. Canadian occurrences of Bryoandersonia illecebra (‘Spoon-leaved Moss Sites’), derived from herbarium specimens (Table 2) and field observations (Table 3). Sites where the species was ‘not observed in 2002’ denote locales where B. illecebra has been collected since 1970 but where the species’ persistence was not confirmed despite searches in 2001-2002.

Figure 5. Canadian occurrences of Bryoandersonia illecebra (‘Spoon-leaved Moss Sites’), derived from herbarium specimens (Table 2) and field observations (Table 3). Sites where the species was ‘not observed in 2002’ denote locales where B. illecebra has been collected since 1970 but where the species’ persistence was not confirmed despite searches in 2001-2002.

All six previously known contemporary sites for Bryoandersonia illecebra were examined in 2001 and 2002 in connection with this status report. Time permitted the examination of two additional nearby sites in Essex County. Concurrent studies of Helodium paludosum, with which B. illecebra is often collected in Canada, facilitated the investigation of seven other promising sites within the known range of B. illecebra in Ontario as well as more than ten sites further north.

Table 1. Summary of search effort devoted to seeking populations of Bryoandersonia illecebra in connection with this report. Sites are described in greater detail in Tables 2 and table 33. Check marks indicate years in which a search was conducted for each site or group of sites. Hours of search effort are approximate. Where no notes are made under ‘Extant population’, no extant population was found.
Reasons for searching Site(s)/th> 2001 200 Search effort (hours) Extant population
Previously known locales Essex 4 4 8 Found in 2002
Previously known locales Middlesex 4   2  
Previously known locales Elgin – Edwards Farm   4 4  
Previously known locales Elgin – West Lorne 4 4 7  
Previously known locales Elgin – Dodd’s Creek   4 7 Found in 2002, but site description does not match that noted by previous collector
Previously known locales Elgin – Jolley’s Swamp   4 5  
Time available (Essex County) Cedar Creek Conservation Area 4 4 4  
Time available (Essex County) Wheatley Provincial Park   4 1.5  
Sites searched for Helodium paludosum Within known Canadian range of B. illecebra (7 sites)   4 25 Found one site in 2002, in Welland County
Sites searched for Helodium paludosum North of known Canadian range of B. illecebra (10 sites)   4 35  

This search effort resulted in the confirmation of three extant populations of Bryoandersonia illecebra:

  1. The persistence of the Essex population was confirmed.
  2. The Welland population, which was previously unknown, was discovered.
  3. Although an extant population was discovered in Elgin County, it is difficult to determine whether or not this population represents a previously known locality. Two specimens collected by William Stewart, bearing identical dates, collecting numbers, and habitat descriptions but apparently from different sites (‘Paynes Mills’ and ‘Edwards Farm’) were discovered at separate herbaria. Eileene Stewart, who accompanied her husband on many collecting trips remembers B. illecebrafrom the Edwards Farm site and gave detailed directions to the location, and William Stewart’s collecting book (housed at the Royal Botanic Garden, Scotland) indicates that on the date reported, he was at Edwards Farm.  However, B. illecebra was discovered along Elgin hiking trail near Payne’s Mills in 2002, and not at the Edwards Farm site. Moreover, the habitat of the extant Payne’s Mills population does not conform to the description given by William Stewart.

Two historical collections of Bryoandersonia illecebraalso exist. One was distributed as part of Thomas Drummond’s (Crum & Anderson 1981, Missouri Botanical Garden 2001) exsiccata set (Musci Americani #192) as Hypnum illecebrum.  This specimen, though uninformative from a Canadian distribution perspective, supports the historical presence of B. illecebra in Canada. The second (undated) collection was included in a folder of fern specimens, reportedly from “Canada. Rocky Mts.”, but New York Botanical Garden staff note that the specimen ‘quite possibly’ came from a more southern locale.

Page details

Date modified: