Tuberous Indian-plantain (Arnoglossum plantagineum) COSEWIC assessment status report : chapter 7

Population Sizes and Trends

Tuberous Indian-plantain occurs in five areas: the shoreline fens of Lake Huron along the west side of the Bruce Peninsula, several riverine meadows of the Maitland and Ausable rivers close to Lake Huron, a newly discovered population on the Thames River, and a single isolated record near Lake Simcoe. Counts made by Keddy (1988) and by the present author in 1998 are of flowering/fruiting plants unless otherwise noted. Counts made by others are generally of flowering and non-flowering plants combined. Since there may be a dozen or more vegetative plants in a population for every flowering plant (pers. obs., 1998), comparisons must be made carefully.

Keddy (1988) reported a single plant south of Orillia near Lake Simcoe (Site 1 on map, Fig. 3). This plant was seen as recently as 1993 or 1994 by the landowner H. Cattley when the single plant produced two flowering stems (H. Cattley, pers. com., 1998).

In 1993, Mike Oldham found a new population of over 100 tuberous Indian-plantain, presumably both flowering and non-flowering plants, along the Thames River (Site 2 on map, Fig. 3). This is the first known occurrence of the species on the Thames River and is about 40 km southeast of the Ausable River sites.

Three subpopulations (all within one kilometre of each other), consisting of one, three, and 18 flowering plants, are listed in Keddy (1988) for the Ausable River near Arkona (Site 3 on map, Fig. 3). The author searched the area with the subpopulation of 18 on 27 July 1998 and found two flowering plants. Oldham (1998) lists four additional records in essentially the same area that were last seen in 1984 and 1985. Two of these populations each contained up to one hundred flowering and non-flowering plants. The author found a new site nearby on 27 July 1998 in the Rock Glen Conservation Area with one flowering and 24 non-flowering plants. Clearly, tuberous Indian-plantain still occurs in this area; however, there is not enough information to tell if the population size has changed since 1988.

There are several records from the banks of the Maitland River within 20 km of Lake Huron. Keddy (1988) confirmed only one record in this area: 59 flowering plants at Benmiller (Site 4 on map, Fig. 3). The author searched this area on 26 July 1998 and found about 50 flowering plants. Oldham (1998) lists a 1987 record of “scattered plants” from north of Holmesville (Site 5 on map, Fig. 3). The author searched this area on 26 July 1998 but saw no flowering tuberous Indian-plantain. The plants may have been eliminated in this area by expanded lawns or by heavy cattle grazing to the river’s edge. Since the meadow vegetation in this area is very thick in other places, the tuberous Indian-plantain could have been missed if it wasn’t in flower/fruit. Oldham (1998) lists another 1987 record from north of Clinton (Site 6 on map, Fig. 3) but without abundance information. The author searched this area on 26 July 1998 but saw no flowering tuberous Indian-plantain. The meadow vegetation in this area is dominated by very dense stands of Reed Canary Grass (Phalaris arundinacea) and the plant could have been missed if it wasn’t in flower/fruit. Oldham (1998) lists three additional records from the banks of the Maitland River (Site 4 on map, Fig. 3): one kilometre southwest of Benmiller in the Falls Reserve Conservation Area, seen in 1995 and recorded as “rare and local”; two kilometres and three kilometres east-southeast of Goderich, both seen in 1993 with no abundance information. Thus, tuberous Indian-plantain is still extant along the Maitland River and is known from several sites not reported on in Keddy (1988).

The principal range of tuberous Indian-plantain in Ontario is along the west side of the Bruce Peninsula. Keddy (1988) lists six main areas, some with several subpopulations. Fieldwork by the present author in 1998 shows that the area supports thousands of flowering/fruiting tuberous Indian-plantain.

At Chief’s Point Bay (Site 7 on map, Fig. 3), Keddy (1988) lists “9 colonies of 1-100”. The author visited these sites 16 July 1998 and counted the nine colonies as four subpopulations because of their close proximity. The number of flowering plants of tuberous Indian-plantain was as follows (Keddy’s 1988 numbers are in parentheses): (138) 420, (100) 75, (20) 124, (100’s) 300+.

At Oliphant South (Site 7 on map, Fig. 3), Keddy (1988) lists “scattered plants” at three locations. The author visited these sites 16 July 1998 and counted five colonies of: 170, 66, 126, 340, and 35 flowering plants.

At Oliphant North (Site 7 on map, Fig. 3), Keddy (1988) lists four sites with: 60, 20, and “a few scattered plants” at two sites. The author visited these sites 16 July 1998 and counted the four colonies as: 200+, 90, 1500+, and 60 flowering plants respectively. The 1500+ colony occurs in the Oliphant Fen Nature Reserve that is owned by the Owen Sound and Saugeen Field Naturalist Clubs.

Keddy (1988) counted “hundreds” of tuberous Indian-plantain at Red Bay (Site 8 on map, Fig. 3). Oldham (1998) lists this site as “Howdenvale Bay - Petrel Point”. The author visited this site 16 July 1998 and counted 1400 flowering plants. Much of this colony occurs in the Petrel Point Nature Reserve, which is owned by the Federation of Ontario Naturalists.

At Pike Bay (Site 9 on map, Fig. 3), Keddy (1988) reported 20 flowering plants. The author visited this site 16 July 1998 and counted 120 flowering plants.

Keddy (1988) found Dorcas Bay (Site 10 on map, Fig. 3) to have “six sites with 10-110+ plants”. The author visited this area 24 July 1998 and due to the proximity of the subpopulations, counted the sites as one colony with 506 flowering plants. This colony occurs partly in Bruce Peninsula National Park, which is owned and managed by Parks Canada, and partly in the Dorcas Bay Nature Reserve, which is owned by the Federation of Ontario Naturalists. The author found two additional colonies nearby: the first colony was one kilometre south of Dorcas Bay with 14 flowering plants; the second was three kilometres south of Dorcas Bay and had 106 flowering plants.

There is a 1948 record of tuberous Indian-plantain from “Southampton, floodplain of Saugeen River” (Site 11 on map, Fig. 3) that Keddy (1988) was unable to relocate. Muriel Andraea (pers. com., 1998) found about 12 flowering tuberous Indian-plantain at this location on 10 July 1998. The plants were on an elevated river terrace in a public park owned by the Town of Southampton where the plants are at considerable risk from mowing (M. Andraea, pers. com., 1998). There was another colony at the south end of Southampton at a stream outlet to Lake Huron; however, this small population was eliminated in about 1970 by shoreline development (M. Andraea and J. Heagy, pers. com., 1998).

Oldham (1998) reports several populations (totalling about 35-40 plants) in the Sucker Creek area that were found by J. Johnson in 1984. This station occurs between Red Bay (Site 8 on map, Fig. 3) and Pike Bay (Site 9 on map, Fig. 3) but was not reported by Keddy (1988). The author looked briefly at this area on 16 July 1998 but saw no flowering tuberous Indian-plantain.

Oldham (1998) reports a 1988 collection (without abundance information) from MacGregor Point Provincial Park (Site 12 on map, Fig. 3). The author searched this area on 22 July 1998 but saw no tuberous Indian-plantain. The habitat appeared suitable and vegetative plants could have been missed.

Tuberous Indian-plantain was found in 1982 at Corisande Bay (Site 13 on map, Fig. 3) by J. Johnson (Oldham, 1998) but no abundance information was given and the record was not listed in Keddy (1988). The author searched this area on 24 July 1998 but found no tuberous Indian-plantain. Since it is a large area that was not thoroughly explored, the species could have been missed. The plant was also found nearby in 1982 at Johnson Harbour-Pine Tree Point (Oldham, 1998).

Tuberous Indian-plantain is reported (without date) from the Cameron Lake fen (near Site 10 on map, Fig. 3) in Cypress Lake Provincial Park, now part of Bruce Peninsula National Park (Oldham, 1998). The author searched this area without success on 24 July 1998 but the locality information is vague and the site searched may have been incorrect. Another location (also near Site 10 on map, Fig. 3) is reported by Oldham (1998) from Bruce Peninsula National Park west of Dyers Bay and found in 1994. No abundance information is listed in Oldham (1998).

There are several historic sites not seen since before the 1988 status report was written: Colpoy Bay, not seen since 1969 (Site 14 on map, Fig. 3); Big Bay, not seen since 1935 (Site 15 on map, Fig. 3); Sauble Beach, not seen since 1951 (Site 16 on map, Fig. 3); Stokes Bay, not seen since 1935 (Site 17 on map, Fig. 3); Wingham, not seen since 1968 (Site 18 on map, Fig. 3); and Tobermory, not seen since 1929 (Site 19 on map, Fig. 3).

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