Key to 13 Species of Gyromitra in North America 
| 1. | Mushroom more or less cup-shaped; without a well defined stem, or with a rudimentary stem structure. (Microscopic analysis will be required to identify species in this group). | 2 |
| 1. | Mushroom not cup shaped; stem well developed. (Microscopic analysis not required in order to identify most species.) | 5 |
| 2. | Upper surface grayish brown to dark brown; spores 10-14.5 x 7-9.5 µ, lacking apiculi (use a water mount). | Gyromitra melaleucoides |
| 2. | Upper surface usually (not always) a version of brown with more red or orange than above; spores much longer than above, often with prominent apiculi (when viewed in a water mount). | 3 |
| 3. | Apiculi of mature spores appearing scooped-out, like a camel's back. | |
| 3. | Apiculi absent or, if present, pointed or broadly rounded. | 4 |
| 4. | Apiculi of mature spores pointed. | |
| 4. | Apiculi absent or, if present, broadly rounded. | Gyromitra olympiana |
| 5. | Cap 2- or 3-lobed; found in fall. | 6 |
| 5. | Cap not as above; found in spring or in summer at very high elevations (near the tree line). | 7 |
| 6. | Cap brownish to orange-brown; spores 17-23 µ long. | |
| 6. | Cap reddish to purplish red; spores 21-30 µ long. | |
| 8. | Cap brainlike, convoluted, reddish; stem without sharp ribs. | |
| 8. | Cap cushionlike, brownish; stem with sharp ribs. | 9 |
| 9. | Western; terrestrial; spores elliptical. | |
| 9. | Northern and western; on wood; spores round. | |
| 10. | Cap squarish; northern, central, and western ( = "Gyromitra gigas," in the wide sense). | 11 |
| 10. | Cap not squarish; central and southern. | 12 |
| 11. | Spores with knobbed ends. | |
| 12. | Cap with ribs and cross-ribs, never lobed; undersurface never exposed. | |
| 12. | Cap without ribs and cross-ribs, irregularly lobed; undersurface often exposed in places. | |
References
Abbott, S. O. & Currah, R. S. (1997). The Helvellaceae: Systematic revision and occurrence in northern and northwestern North America. Mycotaxon 62: 1-125.
Batra, L. R. (1976). Helvella and Gyromitra (Pezizales: Operculatae) in the southern Appalachians. In B. C. Parker & M. K. Roane, eds. Distributional history of the biota of the southern Appalachians. Part IV. Algae & fungi: biogeography, systematics and ecology. Charlottesville, Virginia: University Press of Virginia. 145-204.
Breitenbach, J. & Kränzlin, F. (1984). Fungi of Switzerland: A contribution to the knowledge of the fungal flora of Switzerland. Volume 1 Ascomycetes. Transl. Walters, V. L. & Walters, J. F. Lucern: Verlag Mykologia. 310 pp.
Harmaja, H. (1969). A neglected species, Gyromitra ambigua (Karst.) Harmaja, n. comb., and G. infula s. str. in Fennoscandia. Karstenia 9: 13-19.
Harmaja, H. (1973). Amendments of the limits of the genera Gyromitra and Pseudorhizina, with the description of a new species, Gyromitra montana. Karstenia 13: 48-58.
Kanouse, B. B. (1946). Some studies in the genus Helvella. Papers of the Michigan Academy of Science, Arts and Letters 32: 83-90.
Kuo, M. (2005). Morels. Ann Arbor: University of Michigan Press.
McKnight, K. H. (1969). A note on Discina. Mycologia 61: 614-630.
McKnight, K. H. (1973). Two misunderstood species of Gyromitra (false morel) in North America. The Michigan Botanist 12: 147-162.
O'Donnell, K. O., et al. (1997). Phylogenetic relationships among ascomycetous truffles and the true and false morels inferred from 18S and 28S ribosomal DNA sequence analysis. Mycologia 89: 48-65.
Raitviir, A. (1970). Once more on Neogyromitra caroliniana. Transactions of the Tartu State University 268, Papers on Botany 9: 364-373.
Weber, N. S. (1995). A morel hunter's companion: A guide to true and false morels. Michigan: Thunder Bay Press. 209 pp.
Cite this page as:
Kuo, M. (2006, December). Gyromitra: The false morels. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/gyromitra.html
© MushroomExpert.Com