Plants and Animals
Cirsium hillii Hill's thistle
Short, stout perennial thistle (30-60 cm) of pine barrens, oak savanna, prairie, forest openings, and glade habitats; young plants appearing only as a basal rosette with very shallowly lobed leaves; flower a single large pink head.
Status and Rank
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G3 - Vulnerable
State Rank: S3 - Vulnerable
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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.
Found primarily in pine barrens in northern Lower Michigan, but also occurring in other savanna and prairie types, openings within coniferous and oak forests, and on limestone pavement.
Natural Community Types
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.
Big and little bluestem, blazing star, rough fescue, pale agoseris, Alleghany plum, harebell, juniper, poverty grass, hair grass, western sunflower, Allegheny plum, prairie dropseed, cat's foot, Canadian milk vetch, sedges, Indian paintbrush, field chickweed, bastard toad flax, prairie smoke, ground juniper, bee-balm, and old field goldenrod.
Natural disturbance, particularly fire, is necessary to maintain the openings in pine barrens and other associated habitat required by this species. Plants may persist as vegetative rosettes in the absence of disturbance, and have been observed under relatively mature tree canopies, including pine plantations. However, openings are required to promote flowering, and fire also likely plays a key role in reducing litter and creating habitat for germination and colonization. This species thrives on moderate levels of soil disturbance such as light disking or furrowing, though such activities are detrimental to most other rare plants associated with barrens.
Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment of the investigator.
Survey Period: From first week of June to fourth week of August
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