CPC Plant Profile: Saint John River Oxytrope
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Plant Profile

Saint John River Oxytrope (Oxytropis campestris var. johannensis)

The pinnately compound hairy leaves and purple, butterfly-shaped flowers of Oxytropis campestris var. johannensis. Photo Credit: Hank Tyler
Description
  • Global Rank: T4 - Apparently Secure
  • Legal Status: N/A
  • Family: Fabaceae
  • State: CAN, LB, MB, ME, NB, NF, NS, NU, ON, QC
  • Nature Serve ID: 140595
  • Date Inducted in National Collection: 06/18/1986

Oxytropis campestris var. johannensis is a river-side legume endemic to Maine and eastern Canada. Its deep taproot and compact architecture help it withstand the frequent flooding and ice scour common along wild, rocky northern rivers, and its populations shift along the shoreline when disturbance occurs. Although relatively secure in southern Ontario, the species has declined in extent from 118 km to 28 km of shoreline in its former Maine stronghold along the St. John River (which gave it its common name). Its taxonomic relatedness to the similar but disjunct taxon, Oxytropis campestris var. chartacea (Fassett) Barneby of Wisconsin (U.S. Fish and Wildlife Service 2001, Wisconsin State Herbarium 2001) still need to be resolved; these could constitute the same taxon, meaning the variety is more widespread than previously thought. In any case, populations are threatened by changes in hydrology and sedimentation brought on by damming and riverbed mining and upland clearing, as well as encroachment of invasive species. Research and Management Summary: Apart from preliminary taxonomic treatments, no published research could be located on this taxon. However, the New England Wild Flower Society has performed germination trials on it and published a Conservation and Research Plan in 2001. Plant Description: Oxytropis campestris var. johannensis is a perennial herb growing 4-55 cm tall with short-stems that emanate from a tap-rooted base. Its pinnately-compound leaves consist of 7-45 hairy leaflets each 5-25 mm long. In July, its flowers form at the end of a leafless stem, clustered into a raceme of up to 14 blooms. The 12-18 mm-long flowers are purple or rarely white, with the typical "butterfly" shape of the Papilionoid group. The plant produces sparsely hairy legumes (pods) that are 1.5-2.5 cm long.

Participating Institutions
Updates
  • 09/23/2020
  • Orthodox Seed Banking

The New England Wild Flower Society (Framingham, Massachusetts) has conducted seed germination trials for Oxytropis campestris var. johannensis (Brumback 1989). Fifty seeds collected in early August, 1986 yielded three seedlings within three weeks of sowing. Six additional seedlings also germinated following a three-month treatment in moist cold storage. However, dry, cool storage appeared to promote the best germination. Seed held for 9 years in seed bank conditions remained viable.

  • 09/23/2020
  • Seed Collection

The New England Wild Flower Society (Framingham, Massachusetts) has conducted seed germination trials for Oxytropis campestris var. johannensis (Brumback 1989). Fifty seeds collected in early August, 1986 yielded three seedlings within three weeks of sowing. Six additional seedlings also germinated following a three-month treatment in moist cold storage. However, dry, cool storage appeared to promote the best germination. Seed held for 9 years in seed bank conditions remained viable.

  • 09/23/2020
  • Orthodox Seed Banking

The North American Rock Garden Society also appears to possess seed of Oxytropis campestris var. johannensis.

  • 09/23/2020
  • Propagation Research

The New England Wild Flower Society (Framingham, Massachusetts) has conducted seed germination trials for Oxytropis campestris var. johannensis (Brumback 1989). Fifty seeds collected in early August, 1986 yielded three seedlings within three weeks of sowing. Six additional seedlings also germinated following a three-month treatment in moist cold storage. However, dry, cool storage appeared to promote the best germination. Seed held for 9 years in seed bank conditions remained viable.

Nature Serve Biotics
  • 05/02/2017

Variety reported to be relatively common in Newfoundland and Quebec. Also known from from 7 occurrences in Maine, all on the St. John River.

Elizabeth J. Farnsworth
  • 01/01/2010

As articulated by Haines 2001: Dams that diminish flood magnitudes and otherwise change river hydrology Gravel mining on river shores (particularly in New Brunswick) Trampling by vehicles using river shore as a roadbed Invasive plant species

Elizabeth J. Farnsworth
  • 01/01/2010

Maine harbors six extant populations along the St. John River, down from 14 historically known populations (Haines 2001). Most populations have not been censused recently or have only incomplete counts; current estimates are in the order of magnitude of 1000 plants in Maine (Haines 2001). Populations are more numerous in Ontario, Quebec, and New Brunswick (Catling and Coyouette 2001, NatureServe 2001), but exact numbers are unavailable. Population localities and numbers are likely to vary greatly from year to year due to frequent river disturbance.

Elizabeth J. Farnsworth
  • 01/01/2010

Apart from preliminary taxonomic treatments (Fernald 1899, Barneby 1952, Isley 1998, Welsh in prep.) no published research could be located on this taxon. The New England Wild Flower Society (Framingham, Massachusetts) has conducted seed germination trials for Oxytropis campestris var. johannensis (Brumback 1989). Fifty seeds collected in early August, 1986 yielded three seedlings within three weeks of sowing. Six additional seedlings also germinated following a three-month treatment in moist cold storage. However, dry, cool storage appeared to promote the best germination. Seed held for 9 years in seed bank conditions remained viable. The North American Rock Garden Society also appears to possess seed of Oxytropis campestris var. johannensis.

Elizabeth J. Farnsworth
  • 01/01/2010

A Conservation and Research Plan has been written by Arthur Haines for the New England Wild Flower Society, Framingham, Massachusetts (Haines 2001).

Elizabeth J. Farnsworth
  • 01/01/2010

Field data are urgently needed covering all aspects of the life history of the taxon, including pollination, reproductive output, nodulation activity, metapopulation dynamics, seed dispersal, and the genetic structure of populations. Current and potential impacts of invasive species on the taxon must be critically assessed. Taxonomic relatedness of Oxytropis campestris var. johannensis to Oxytropis campestris var. chartacea and other members of the O. campestris complex should be determined to evaluate the conservation status of both taxa.

Elizabeth J. Farnsworth
  • 01/01/2010

Ex situ germination techniques appear to be relatively well-known for this taxon.

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Photos
Nomenclature
Taxon Oxytropis campestris var. johannensis
Authority Fern.
Family Fabaceae
CPC Number 3069
ITIS 529327
USDA OXCAJ
Common Names Johann's locoweed | late yellow locoweed | St. John river oxytrope | St. John's oxytrope
Associated Scientific Names Oxytropis campestris var. johannensis | Oxytropis johannensis | Aragallus johannensis | Oxytropis campestris var. americana | Oxytropis johannensis f. bicensis
Distribution Oxytropis campestris var. johannensis is endemic to northern Maine, Manitoba, New Brunswick, Nova Scotia, Ontario, and Quebec. It is also reported (but unverified) from Labrador, Newfoundland, and th
State Rank
State State Rank
Canada N4
Labrador S1
Manitoba S1?
Maine S1
New Brunswick S2
Newfoundland S1S3
Nova Scotia S2
Nunavut SNR
Ontario S4
Quebec S3S4
Habitat

Oxytropis campestris var. johannensis is primarily found along gravelly and rocky shores of rivers, on cobbles, beaches, rock outcrops, ledges, and cliffs (Gleason and Cronquist 1991, Haines 2001). In New England, the taxon appears to prefer circumneutral rock types (Haines 2001). The shores where the taxon occurs are subject to seasonal heavy ice scour during snowmelt, and this type of disturbance keeps the area open and conducive to colonization by this plant and others, like the Furbish lousewort (Pedicularis furbishiae), that are poor competitors with other plants in more stable habitats. Along the St. John River in Maine and New Brunswick, the plant occurs at elevations between 160 and 190 m. The relatively pristine St. John River, coursing through calcareous glacial tills and bedrock, hosts a uniquely diverse array of rare and specialized plant species in the region, and possesses extremely high conservation significance (Haines 2001). The species is also reported from the mixed-woods plains ecotone of southern Ontario, along the intertidal freshwater zone of the lower St. Lawrence River estuary (Catling and Cayouette 2001). According to Haines (2001), associated plants include: dwarf sand cherry (Prunus pumila var. depressa); tufted hairgrass (Deschampsia caespitosa); alpine milk-vetch (Astragalus alpinus var. brunetianus); Lake Huron tansy (Tanacetum bipinnatum ssp. huronense); cut-leaved anemone (Anemone multifida); chives (Allium schoenoprasum); northern meadow groundsel (Senecio pauperculus); and alpine sweetbroom (Hedysarum alpinum var. americanum).

Ecological Relationships

Next to nothing is known of the ecological relationships or plant-animal interactions of Oxytropis campestris var. johannensis (Haines 2001), so hypotheses about its ecology must be gleaned from studies of related taxa in the O. campestris complex. The taxon flowers from June to July in Maine, and fruits develop and mature in July (Haines 2001). In one population studied by Haines (2001), about 50% of the plants flowered in each of two years. Insect pollinators would be expected for the papilionaceous flowers, and bees may be attracted to the purple color, but this has yet to be studied. Seeds are likely to be dispersed by river water. Seed germination is likely sensitive to water level (enhanced when water levels drop in spring) and by rising summer temperatures following snowmelt, if Oxytropis campestris var. johannensis behaves like var. chartacea (Wisconsin Department of Natural Resources 2001) or like a related riparian species, Oxytropis riparia (Delaney 1986). Herbivory rates have not been reported for this taxon. However, the plant may produce secondary compounds (principally flavinoid glycosides) that are toxic to potential herbivores, much as other members of the """"locoweed"""" genus do (Sun 1991). Finally, it is unknown whether Oxytropis campestris var. johannensis harbors nitrogen-fixing rhizobial root symbionts. Nodulation has been documented for several other Oxytropis species (Laguerre 1997), so it might be expected in this taxon, particularly given its affinity for calcareous habitats.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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