Rediscovery of Crataegus pisifera (Rosaceae: Maleae)
Keywords:Hawthorn, endemic microspecies, Vermont botanical history, second step lectotypification
Field searches in 2021 resulted in rediscovery of the pea-fruited hawthorn, Crataegus pisifera Sarg. (C. succulenta var. pisifera (Sarg.) Kruschke), a Vermont endemic known with confidence only from the type collections made in 1901. Collections made throughout the 2021 growing season from the type locality and from new populations nearby confirm its continued presence on the Vermont landscape. Additional morphological characterization is presented and deviations from the original description are discussed. Mature fruits in late October measured 7.2–11.2 mm in diameter, averaging 9.2 mm, larger than the immature fruits described in the literature. Thus, fruit diameter fails to separate C. pisifera from closely related C. succulenta varieties. We present a key, the first range map, and the first published illustrations of this long-lost species; we also include a second-step lectotypification that clarifies which of two available herbarium sheets is the one to be regarded as the lectotype.
ASHE, W.W. 1899. New East American species of Crataegus. Contributions from my herbarium No. VI. J. Elisha Mitchell Sci. Soc. 16(2):71–72.
CPC (CORNWALL PLANNING COMMISSION). 2013. Cornwall Town Plan. Available at cornwallvt.com. Accessed 30 Aug 2021.
DEEPL TRANSLATOR. DeepL GmbH, Cologne, DE. Available at deepl.com. Accessed 31 Jul 2022.
DICKINSON, T.A. 2018. Sex and Rosaceae apomicts. Taxon 67(6):1093–1107.
DOLE, E.J., ED. 1937. Flora of Vermont, ed. 3. Free Press Printing Company, Burlington, VT, U.S.A.
EGGLESTON, W.W. 1908. Crataegus. In: B.L. Robinson & M.L. Fernald, eds. Gray’s new manual of botany, ed. 7. Pp. 460–479.
EGGLESTON, W.W. 1913. Crataegus. In: N.A. Britton & A. Brown. An illustrated flora of the northern United States and Canada, ed. 2. Charles Scribner’s Sons, New York, U.S.A. 2:294–320.
EVANS, R.C. & T.A. DICKINSON.1996. North American black-fruited hawthorns. II. Floral development of 10 and 20-stamen morphotypes in Crataegus Section Douglasii (Rosaceae: Maloideae). Amer. J. Bot. 83(8):961–978.
GILMAN, A.V. 2015. New flora of Vermont. Mem. New York Bot. Gard. 110.
GLEASON, H.A. & A. CRONQUIST. 1963. Manual of vascular plants of northeastern United States and Adjacent Canada. D. Van Nostrand Company, New York, U.S.A.
GLEASON, H.A. & A. CRONQUIST. 1991. Manual of vascular plants of northeastern United States and Adjacent Canada, ed. 2. New York Botanical Garden, Bronx, NY, U.S.A.
HAINES, A. 2011. Flora Novae Angliae. Yale University Press, New Haven, CT, U.S.A.
KALKMAN, C. 2004. Rosaceae. In: Kubitzki, K., ed. The families and genera of vascular plants. Springer-Verlag, New York, U.S.A., Berlin, Germany. 6:343–386.
KRUSCHKE, E.P. 1955. Hawthorns of Wisconsin, Part 1. Milwaukee Public Museum Publications in Botany No. 2. Milwaukee, WI, U.S.A.
MAJESKÝ, L., F. KRAHULEC & R.M. VAŠUT. 2017. How apomictic taxa are treated in current taxonomy: a review. Taxon 66 (5):1017–1040.
MATTHEWS, L. 1862. History of the town of Cornwall, Vermont. Mead and Fuller, Middlebury, VT, U.S.A.
PALMER, E.J. 1937. In: E.J. Dole, ed. The flora of Vermont, 3rd revised ed. Free Press Printing Company, Burlington, VT, U.S.A.
PALMER, E.J. 1946. Crataegus in the northeastern and central United States and adjacent Canada. Brittonia 5(5):471–490.
PALMER, E.J. 1950. Crataegus. In: M.L. Fernald. Gray’s manual of botany, ed. 8. American Book Company, New York, U.S.A.
PALMER, E.J. 1952. Crataegus. In: H.A. Gleason. The New Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. The New York Botanical Garden/Hafner Press, New York, U.S.A. 2:338–374.
PHIPPS, J.B. 2007. Kruschke names in North American Crataegus. J. Bot. Res. Inst. Texas 1(2):1011–1014.
PHIPPS, J.B. 2014. Crataegus. In: Flora of North America Editorial Committee, eds. Flora of North America north of Mexico. Oxford University Press, New York, U.S.A., and Oxford, U.K. 9:491–643.
RONSE DE CRAENE, L.P. 2010. Floral diagrams: An aid to understanding flower morphology and evolution. Cambridge University Press. New York, U.S.A., and Cambridge, U.K.
SARGENT, C.S. 1905a. Recently recognized species of Crataegus. Rhodora 7:162–164.
SARGENT, C.S. 1905b. Manual of the trees of North America. Houghton Mifflin and Company, Boston and New York, U.S.A.
SEYMOUR, F.C. 1969. The flora of Vermont, ed. 4. Vermont Agric. Exp. Stat. Bull. 660. Burlington, VT, U.S.A.
SEYMOUR, F.C. 1969B. The flora of New England. Charles E. Tuttle Company, Rutland, VT, U.S.A.
USGS (United States Geologic Survey). 1894. New York–Vermont Ticonderoga Quadrangle topographic map (1:62,500). US Department of the Interior, Reston, VA, U.S.A.