Plants and Animals
Wolffiella gladiata Flordia mudmidget
Key Characteristics
The whole body of the plant consists of a single, sword or scythe–shaped frond that lacks leaves, stems, and roots and rarely flowers. The frond is linear or needle-like and ranges from 3–9 mm (0.1–0.4 in) long and less than 1 mm (0.04 in) wide. It can be found as a single frond, but often fronds are found cohered in clumps that appear to originate from a single base. These clumps become hemispherical as they increase in size, which can resemble a mop head or jellyfish dangling below the water’s surface. The clumps then cling together to form floating mats. Florida mudmidget can be distinguished from other duckweeds by its simple, linear frond and lack of roots. It is much larger and longer than species of Wolffia, which are the only other duckweeds that lacks roots (Reznicek et. al. 2011). Star duckweed (Lemna trisulca) is the most likely to be confused for Florida mudmidget as it also forms underwater, interconnected clumps, but the frond differs in shape.
Status and Rank
US Status: No Status/Not Listed
State Status: T - Threatened (legally protected)
Global Rank: G4G5 - Rank is uncertain, ranging from apparently secure to secure
State Rank: SNR - Not ranked
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Bay | 1 | 2000 |
| Cass | 1 | 1915 |
| Eaton | 1 | 2016 |
| Genesee | 1 | 1964 |
| Gratiot | 2 | 2023 |
| Hillsdale | 1 | 1988 |
| Ingham | 2 | 1892 |
| Kalamazoo | 1 | 1950 |
| Macomb | 3 | 2012 |
| Oakland | 1 | 1918 |
| St. Joseph | 1 | 1915 |
| Van Buren | 1 | 1915 |
| Washtenaw | 3 | 2012 |
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
Florida mudmidget occurs in shaded, sheltered, shallow bodies of water, or along shorelines, often with other duckweeds. The Michigan population was discovered in a mucky-bottomed seepage lake. It also occurs in nearby northwest Indiana where populations occurred in shallow pools near the shores of lakes as well as shaded ponds.
Specific Habitat Needs
Pool needed in: Mesic southern forest.
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.
Associated Plants
Buttonbush, silver maple, red ash, spicebush, poison ivy, and southern blue-flag.
Management Recommendations
A status survey for this species is warranted to better understand its extent and habitat requirements in Michigan. This species requires conservation of shaded, slowmoving water bodies, regulation of nutrient inputs, and protection of hydrological regimes.
Survey Methods
Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment of the investigator.
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Meander search
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Survey Period: From first week of July to fourth week of August
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References
Survey References
- Elzinga, C.L., D.W. Salzer, and J.W. Willoughby. 1998. Measuring and Monitoring Plant Populations. The Nature Conservancy and Bureau of Land Management, Denver. BLM Technical Reference 1730-1. 477pp.
- Goff, G.F., G.A. Dawson, and J.J. Rochow. 1982. Site examination for Threatened and Endangered plant species. Environmental Management 6(4): 307-316
- Nelson, J.R. 1984. Rare Plant Field Survey Guidelines. In: J.P. Smith and R. York. Inventory of rare and endangered vascular plants of California. 3rd Ed. California Native Plant Society, Berkeley. 174pp.
- Nelson, J.R. 1986. Rare Plant Surveys: Techniques For Impact Assessment. Natural Areas Journal 5(3):18-30.
- Nelson, J.R. 1987. Rare Plant Surveys: Techniques for Impact Assessment. In: Conservation and management of rare and endangered plants. Ed. T.S. Elias. California Native Plant Society, Sacramento. 8pp.
Technical References
- Braun, E. L. 1967. The Monocotyledoneae of Ohio. Cat-tails to Orchids. Ohio State University Press, Columbus. 464pp.
- Flora of North America Editorial Committee. 2002. Flora of North America, North of Mexico. Volume 23: Magnoliaphyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York. 608pp.
- Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. 2nd Ed. The New York Botanical Garden, New York, New York.
- Gray, A. 1950. Gray's Manual of Botany; eighth ed. Van Nostrand Reinghold, New York. 1632pp.
- Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the vascular plants of Northeastern United States and adjacent Canada. New York Botanical Garden, Bronx. 937pp.
- Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region, 4th ed. Indiana Academy of Science, Indianapolis. 921pp.
- Voss, E. G. 1972. Michigan Flora. Part I. Gymnosperms and Monocots. Bulletin of the Cranbrook Institute of Science and University of Michigan Herbarium. 488pp.