Hypericum adpressum
Creeping St. John's-wort
Image of Hypericum adpressum

Photo by Brad Slaughter 

Key Characteristics

Medium-sized rhizomatous forb (40-80 cm) of coastal plain marshes; leaves in whorls, narrowly elliptic to lanceolate and revolute, pinnately veined, 3.5-7 cm long; flowers 1-2 cm wide, yellow, in terminal clusters, sepals revolute.

Status and Rank

  • State Status: T
  • State Rank: S1
  • Global Rank: G3

Occurrences

County NameNumber of OccurrencesYear Last Observed
Newaygo22006
Distribution map for Hypericum adpressum

Updated 1/31/2017. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

First collected in Michigan in 2005, this species is known only from the margins of coastal plain marshes.

Natural Community Types

Methodology

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Bluejoint grass, prairie cordgrass, panic grass, wool-grass, three-way sedge, wire sedge, black-fruited spikerush, tall beak-rush, Canadian rush, hyssop hedge-nettle, lance-leaved violet, meadow-beauty, grass-leaved arrowhead, northern bugleweed, fireweed, Canadian St. John's-wort, larger Canadian St. John's-wort, lakes flat-topped goldenrod, southern blue flag, swamp dewberry, meadowsweet, and steeplebush.

Management

This species requires conservation of habitat and protection of the hydrology, including maintenance of cyclical drawdown regime and water table. Maintain moist, open habitat. It is also vulnerable to ORV impacts and dredging and filling activities.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgement of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Jun 27, 2017]

References

Survey References

Technical References

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