Conservation implications of spur length variation in long-spur columbines (Aquilegia longissima)

Abstract

Populations of long-spur columbine (Aquilegia longissima) with spurs 10-16 cm long are known only from a few populations in Texas, a historical collection near Baboquivari Peak, Arizona, and scattered populations in Coahuila, Chihuahua, and Nuevo Leon, Mexico. Populations of yellow columbine with spurs 7-10 cm long are also found in Arizona, Texas, and Mexico, and are now classified as A. longissima in the recent Flora of North America. In a multivariate analysis of floral characters from 11 yellow columbine populations representing a continuous range of spur lengths, populations with spurs 10-16 cm long are clearly separate from other populations based on increasing spur length and decreasing petal and sepal width. The longer-spurred columbines generally flower after monsoon rains in late summer or fall, and occur in intermittently wet canyons and steep slopes in pine-oak forests. Also, longer-spurred flowers can be pollinated by large hawkmoths with tongues 9-15 cm long. Populations with spurs 7-10 cm long cluster with the common golden columbine (A. chrysantha), and may be the result of hybridization between A. chrysantha and A. longissima. Uncertainty about the taxonomic status of intermediates has contributed to a lack of conservation efforts for declining populations of the long-spur columbine.

Parent Publication

• Southwestern rare and endangered plants: Proceedings of the Fourth Conference

Citation

Stubben, Christopher J.; Milligan, Brook G. 2007. Conservation implications of spur length variation in long-spur columbines (Aquilegia longissima). In: Barlow-Irick, P.; Anderson, J.; McDonald, C., tech eds. Southwestern rare and endangered plants: Proceedings of the Fourth Conference; March 22-26, 2004; Las Cruces, New Mexico. Proceedings. RMRS-P-48CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 108-114