Hasteola suaveolens (L.) Pojark.
Sweet-smelling Indian plantain
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Synosma suaveolens, Cacalia suaveolens
Basis for Listing
Hasteola suaveolens reaches the northwestern limit of its range in Minnesota and was probably uncommon here even before human settlement. Since the time of settlement, populations have been reduced to critically low numbers by extensive wetland drainage in southeastern Minnesota. Unrestricted ditching and tiling has essentially eliminated wetlands from the landscape of that region. This loss of wetlands has reduced the habitat of H. suaveolens to tiny, scattered remnants, whose quality may be further diminished by herbicide run-off from agricultural land. Similar patterns of environmental degradation appear to threaten this species throughout much of its range. There are even indications that it is declining in several states within the center of its range. Hasteola suaveolens was listed as an endangered species in Minnesota in 1984. As of 2008, there were fewer than 15 known occurrences in the state.
Hasteola suaveolens is a tall, perennial herb with a characteristic appearance. Most distinctive are the leaves, which are alternate, triangular, tapering to a long point, shaped much like an arrowhead, with double rows of sharp, forward- pointing teeth, and winged stems. Flowers are creamy white to pinkish, with 20-40 per head, arranged in flat-topped clusters.
The native habitat of H. suaveolens in Minnesota appears to be moist riverbanks, wet meadows along stream courses, and the edge of marshes. The population in the Kellogg-Weaver Bottoms area occurs in a wet meadow on the Mississippi River floodplain.
Biology / Life History
A perennial plant, H. suaveolens is known to spread by rhizomes and by seeds. At the northern limits of its range it appears to be at a disadvantage due to its late-season flowering and seeding (Sharp 2000).
Conservation / Management
It has been surmised that H. suaveolens depends upon dynamic riverine habitats subject to scouring and flooding. Damming of rivers may, in part, account for the decline of this species. Managing stream flow to mimic spring flooding may create suitable habitat. The draining and filling of wetlands throughout the region has also eliminated extensive habitats. Wetland protection is essential. Invasive plants, particularly Phalaris arundinacea (reed canary grass), threaten to crowd and displace H. suaveolens in some habitats. Monitoring of H. suaveolens populations for invasive plants and the eradication of invasive plants is needed. White-tailed deer (Odocoileus virginianus) will browse this plant, and the overpopulation of deer in some areas could pose a threat to population viability. Reduction in the deer herd in these areas would benefit this species and the many other rare plants that are adversely impacted by white-tailed deer (Sharp 2000). Livestock grazing and herbicide use are considered incompatible with habitat management goals. Further research is need on the biology and ecology of this species. There has been an expressed need for information about seed viability and pollinators. Proactive surveys in suitable habitat are advised (Sharp 2000).
Conservation Efforts in Minnesota
No conservation efforts have been undertaken specifically on behalf of this species. One of the H. suaveolens populations in Fillmore County and the only population in Wabasha County are located in state Wildlife Management Areas, which may provide some level of protection. All other known populations are on private land.
References and Additional Information
Gleason, H. A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. Second Edition. New York Botanical Garden, Bronx, New York. 910 pp.
Nekola, J. C. 1990. Rare Iowa plant notes from the R. V. Drexler Herbarium. Journal of the Iowa Academy of Sciences 97(1):55-73.
Sharp, P. P. 2000. Conservation and Research Plan, Hasteola suaveolens (L.) Pojark., Sweet Indian Plantain. New England Wildflower Society, Framingham, Massachusetts.