| Artemisia senjavinensis Besser | |
| Publ. & Syn. | Artemisia androsacea Seem., Bot. Voy. Herald: 34 (1852). Described from Alaska. |
| Notes | Yurtsev and Korobkov: We propose the northwestern North American Artemisia androsacea and the northeastern Asian A. senjavinensis to be two different species. We accept that A. androsacea is closely related to A. senjavinensis and may be considered a subspecies of it (subsp. androsacea (Seem.) Jurtz. & Korobkov ined.). The difference is in growth form. Artemisia senjavinensis is a true cushion xeric semishrub with all internodes abbreviated, forming column-like sheaths congested in taller cushions, whereas A. androsacea forms flat, lax mats because the growth of each new branch of its caudex starts with elongated prostrate internodes. In its driest habitats A. androsacea forms compact mats but never as tall as a cushion of A. senjavinensis s. str. Only hexaploids are recorded in A. senjavinensis s. str. on the Chukchi Peninsula (southeastern extremity of the peninsula), whereas tetraploids and hexaploids are known from the Seward Peninsula. There seems to be no correlation between ploidy level and morphological features, probably autopolyploidy. Both taxa are obligate calciphytes, cryoxerophytes of dry limestone summits, crests and slopes (including screes), but the American plant occurs in carbonate scree more often than the Asian one. Murray and Elven: We have compared Chukotkan and Alaskan material (ALA, O, S, in the field) and find no morphological difference whatsoever in compactness or in other features. Alaskan plants from exposed sites are just as compact as are Chukotkan ones. There is no visible morphological difference between Alaskan tetraploids and hexaploids. As a previously assumed ploidy difference between Alaskan and Chukotkan plants also has been disproved, the two names should be synonymized (as done by, e.g., Ling 1996). We recognize only one species for the Checklist. |
| Chromosomes | (1) 36 (4x). - Alaska. - Dawe and Murray (1981c); Murray and Kelso (1997). Five counts. (2) 54 (6x). - Far East, Alaska. - Korobkov (1972, 1981); Dawe and Murray (1981c). |
| Geography | Amphi-Beringian: RFE ALA. |
| Distribution | E = R CE = r AW = r [ key ] |
| Parent taxon | Artemisia L. |
| PAF ID | 862216 |