Panarctic Flora


361208 Ranunculus trichophyllus Chaix


Northern Fennoscandia: Rare
Kanin - Pechora: Presence uncertain
Polar Ural - Novaya Zemlya: Presence uncertain
Taimyr - Severnaya Zemlya: Presence uncertain
Anabar - Onenyo: Presence uncertain
Kharaulakh: Presence uncertain
Yana - Kolyma: Presence uncertain
West Chukotka: Rare
East Chukotka: Scattered
Western Alaska: Rare
Northern Alaska - Yukon: Rare
Central Canada: Present only in the Borderline Arctic
Western Greenland: Presence uncertain
Eastern Greenland: Presence uncertain
Shrub Tundra: Rare
Bordering boreal or alpine areas: Frequent

2n= (1) 32 (4x). - Europe, Russia, Siberia, Far East, Canada. - Numerous reports, some for Batrachium kaufmannii and B. trichophyllum.
(2) 48 (6x). - Europe. - At least four reports, at least 16 counts from Denmark and Sweden alone.
Not included: Reports of 2n = 16, e.g., Löve and Solbrig (1964a, Manitoba). These probably belong to Ranunculus circinatus or R. subrigidus.

Geography: Circumboreal?: NOR RUS? SIB? RFE ALA (CAN) GRL?.

Notes: We consider Ranunculus trichophyllus apart from R. aquatilis L. Sp. Pl.: 556 (1753); lectotype (LINN): Europe. Herb. Linn. 715.75 (Cook 1967: 123, as "neotype"); [Batrachium aquatile (L.) Dumort., Bull. Soc. Roy. Bot. Belgique 2: 215 (1863)]. The diagnostic characters reported for R. aquatilis vs. R. trichophyllus (= R. aquatilis var. diffusus, see Dahlgren and Jonsell 2001: 264) should be enough to justify different species in this group: laminate floating leaves regularly present vs. never; pedicels mostly 1.5-3.5 cm, stout and strongly reflexed vs. mostly 2.5-7 cm, slender and slightly reflexed; petals (honey leaves) obovate and contiguous vs. narrowly obovate and not contiguous (usually well separated); and nectaries usually cup-shaped vs. lunate. However, only one of these characters is applicable on the vegetative plants often found in the Arctic (the leaf type). The plants that reach the Arctic in Europe, Alaska, and Canada are of the type with filiform-dissected leaves only (R. trichophyllus). Ranunculus aquatilis reaches north to non-arctic northern Norway and non-arctic southwestern Alaska.

All geographical records should be carefully considered. Ranunculus trichophyllus was found in 2002 beyond and at the arctic boundary in western (ALA; the Seward Peninsula) and northern Alaska (ALA, O; the Noatak River valley) and is also vouchered from the Borderline Arctic at Kazan River below Yathkyed Lake in mainland Nunavut (CAN). Revision of the material in ALA and CAN has not revealed additional arctic localities in Alaska or Canada. Parts of the sparse material we have seen from the southern half of western Greenland (O) is coarse and conform better to R. trichophyllus than to R. confervoides.

Rebristaya and Elven: Tzvelev proposed Batrachium divaricatum (Schrank) Schur 1866 to be the valid species name instead of B. trichophyllum. Within Ranunculus, R. trichophyllus Chaix 1786 has priority before R. divaricatus Schrank 1789.

Higher Taxa