Strophostyles helvola (Fabaceae) in New Hampshire

Abstract

Strophostyles helvola (L.) Elliott, an annual vine in the legume family (Fabaceae), is a recently documented species for New Hampshire. Five populations have been discovered in the last seven years in Brentwood, Concord, and Nottingham, towns located in the south-central and southeastern part of the state (Merrimack and Rockingham counties). In New England, S. helvola was previously known from Connecticut, Massachusetts, Maine, and Rhode Island (Consortium of Northeastern Herbaria 2019), where it reaches the northeast edge of its range (Kartesz 2015). In these states, it is found mostly on the coastal plain in nutrient-poor, disturbed, sandy soil (Haines 2011; Seymour 1969) and is considered native except in Maine, where its nativity status is undetermined. More broadly, S. helvola is considered native across its entire range in the eastern United States and Canada (Gleason and Cronquist 1991; Kartesz 2015). It is ranked as uncommon in Michigan (S3–Vulnerable) and rare in Québec (S1S2–Critically Imperiled/