Panarctic Flora

640301-02 The Aruncus dioicus aggregate A. asiaticus, A. kamtschaticus

2n= 18 (2x). - Europe (C), Russia, Far East (S), Canada (W), U.S.A. (W). - Numerous reports.

Geography: European (C-S) & Asian (C) & Asian (NE) - amphi-Pacific & North American (E).

Notes: Pojarkova (1939) proposed the Aruncus dioicus group as a series of species. She restricted the name A. sylvester to the Caucasus populations, described the main plant of central and northern Asia and the southern Russian Far East as A. asiaticus, and she accepted the plant of northeastern Asia and northwestern North America as A. kamtschaticus. Gladkova (PAF proposal) followed Pojarkova and named the arctic plants A. kamtschaticus. However, also their A. asiaticus reaches the Arctic (Polozhij 1988b). Hultén (1946) found it difficult to accept Pojarkova's species based on the variable criteria indicated. Hara (1955), in the most recent larger revision, proposed the taxa as varieties. The taxa are major, mainly allopatric, and possibly quite old. Subspecific combinations are not available. Pending a modern critical treatment, the two more narrowly circumscribed species are entered.

Aruncus dioicus s. str. is eastern North American and does not approach the Arctic: A. dioicus (Walter) Fernald, Rhodora 41: 423 (1939) [Actaea dioica Walter, Fl. Carol.: 152 (1788), described from southeastern U.S.A.]. Other early names in this group are: (1) Spiraea aruncus L., Sp. Pl.: 490 (1753), described from Austria and France (Auvergne), lectotype (BM-000647516): Herb. Clifford: 463, Aruncus 1 (Cullen in Cafferty and Jarvis 2002a: 544); and (2) Aruncus sylvester Kostel., Index Hort. Bot. Prag.: 15 (1844) nom. nud., probably based on plants from the Caucasus.