Rediscovery of Crataegus pisifera (Rosaceae: Maleae)

Abstract

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.