2019 ASHS Annual Conference

Chrysanthemum arcticum and its two subspecies (C.a. subsp. arcticum, C.a. subsp. polare) are the only Chrysanthemum species native to North America. The centers of origin and diversity are the State of Alaska. This species is salt tolerant, growing only in coastline areas, as well as in acidic soils. Chrysanthemum arcticum may be endangered and is of interest for conservation as well as for evolutionary and genetic studies and a source for new product development. Its dwarf and spreading plant habit plant would be useful to incorporate into new series of winter-hardy, groundcover types. Our research objectives were to characterize and quantify plant morphological traits existing in extant populations from the Aleutian Islands and mainland Alaska. Clones from extant populations of C. arcticum and C.a. subsp. arcticum were used in this study. Morphological traits examined for phenotypic variation included the number of days to visible bud (VBD) and flowering, plant/stem/inflorescence height, flower diameter and petal length, number of leaves and internode lengths, as well as leaf morphology. After 6 weeks (1000 hrs) of cold, VBDs of C.a. subsp. arcticum occurred as early as 28 d while flowering commenced 9 d later (37 d) under long days; C. arcticum, however, took longer for both traits. Thus, C. arcticum differs from cultivated C. xgrandiflorum which is a short day plant. Analysis of the other morphological traits also demonstrated significant variation among populations. Future studies could examine how morphology of extant populations differs from our extensive collection of herbaria specimens to determine potential genetic bottlenecks in the species.