|Title||Observations on the Michigan flora. VI. Distribution records of some angiosperms new, rare, or misinterpreted in the state|
|Publication Type||Journal Article|
|Year of Publication||1957|
Michigan, in the center of the Great Lakes region, seems to be an area unknown or poorly known botanically, to judge from the omissions in many published maps or statements of distribution. An up-to-date state flora, now in preparation, will do much to correct this situation. The present paper discusses the distribution in Michigan of 43 species which I have collected in past years, before formal commencement of the state flora project, and which for a variety of reasons seem to warrant some mention without further delay. The records fall, in general, into the following categories. The Carex flora of the state has been so thoroughly presented by F. J. Hermann (1941, 1951) that additional records of assuredly rare species or significant range extensions in the region are of special interest. New records of this sort are given briefly for C. umbellata, C. exilis, C. leptalea var. harperi, C. michauxiana, C. schweinitzii, and C. sparganioides. Several indigenous species are so rare and local that additional occurrences are valuable to record: Listera auriculata (one previous locality), Primula mistassinica (one previous inland locality), Agoseris glauca (no previous Michigan record), and Aster nemoralis (three previous localities). A third station for the introduced Epipactis helleborine, much farther north than for the previous two, is noted. At least five species illustrate the pattern of Coastal Plain disjuncts which has fascinated plant geographers: Eleocharis melanocarpa, Fuirena pumila. Psilocarya scirpoides, Solidago tenuifolia, and S. remota. In addition, several other species frequently share the restricted habitats of the Coastal Plain plants and by some botanists have been considered to have similar affinities, though actually of wider distribution. These include Fimbristylis autumnalis, Hemicarpha micrantha, Rhynchospora macrostachya, Xyris caroliniana, X. montana, Rhexia virginica, and Stachys hyssopifolia. The statements in current manuals regarding the ranges of some of these do not suggest that they occur in or near Michigan, and as they are often the subject of hypotheses on the part of plant geographers, their distribution should be more accurately known. Other indigenous species which for phytogeographic reasons warrant discussion are a few for which various published reports include decided inadequacies regarding their northern or southern limits of range in the Great Lakes area: Claytonia caroliniana, Dicentra canadensis, D. cucullaria, Dentaria laciniata, Viola incognita, and Viola selkirkii. This small sampling may suggest that Michigan ought not be the terra incognita which manuals, monographs, and phytogeographic papers too often imply. Data are given for nine weeds or adventives of limited occurrence: Silene cserei, Epilobium hirsutum, Oenothera nuttallii, Centaurium minus, Knautia arvensis, Centaurea jacea, Berberis vulgaris, Cirsium palustre, and Tragopogon dubius. In addition, these recently introduced weeds or escapes from cultivation are presented with summaries of previous North American records: Bromus squarrosus, Gypsophila acutifolia, Linaria dalmatica, Centaurea diffusa, and Filago arvensis. Whether these plants become abundant throughout the country, hold their own, or tend to decrease, it is important to place on record as much as is known of their introduction and spread thus far.