Comarum

Scientific name

Comarum L.

Common names

marsh cinquefoil, swamp cinquefoil, purple cinquefoil, purple marshlocks

Family

Rosaceae

Similar genera

Potentilla, Ranunculus

Native distribution

Eurasia, North America

Species cultivated

Comarum palustre L. [offered under the synonym Potentilla palustris (L.) Scop.]

Adventive distribution

none

Weed status

not weedy

Habit

amphibious amphibious:
(adj) of a plant able to live on land or in water
or emergentemergent:
(adj) (syn. emersed) with parts raised out of the water; extending up out of the water
, stoloniferious and rhizomatousrhizomatous:
(adj) possessing rhizomes
herb

Brief description

Stem ascending to erect, sometimes floating, often rooting at nodes, glabrousglabrous:
(adj) without hairs or scales
in lower part, hairy above, reddish. Leaves alternatealternate:
(adj) (of leaves) bearing one leaf per node; placed singly on the stem at different heights
; petiolatepetiolate:
(adj) relating to or in the form of a petiole; bearing petioles
, becoming sessilesessile:
(adj) attached directly, without a stalk
along stem; stipules mostly adnate to petiolepetiole:
(n) the stalk of a leaf
; leaf bladeblade:
(n) (syn. lamina) the flat, expanded part of a leaf, frond, or petal (excluding, e.g., the petiole)
compound (imparipinnate), overall leaf orbicularorbicular:
(adj) circular in outline
to oblongoblong:
(adj) two to four times longer than wide, with +/- parallel sides
; leaflets sessilesessile:
(adj) attached directly, without a stalk
or subsessile, lanceolatelanceolate:
(adj) lance-shaped; widest point below the middle, tapering to the apex
to ellipticelliptic:
(adj) in the form of an ellipse (oval)
or obovateobovate:
(adj) ovate, with the narrow end at the base
, glabrousglabrous:
(adj) without hairs or scales
to sparsely strigosestrigose:
(adj) with stiff, straight, sharp, appressed hairs
, apexapex:
(n) the point farthest from the point of attachment; the tip (often pointed)
obtuse or acuteacute:
(adj) tapering to a sharp, pointed apex with more or less straight sides; broader than acuminate; forming an angle of less than 90 degrees
, base attenuateattenuate:
(adj) narrowing gradually to a point
, marginmargin:
(n) edge; rim
serrate, venationvenation:
(n) the arrangement of veins in a leaf
pinnatepinnate:
(adj) in the form of a feather; of, e.g., leaflets, lobes, or veins: arranged in two rows along an axis
. Inflorescenceinflorescence:
(n) the arrangement of flowers on the floral axis
a terminalterminal:
(adj) at the apex
or axillaryaxillary:
(adj) in, of, or produced from an axil
cyme, 1-10-flowered; pedunclepeduncle:
(n) the stalk of a flower cluster or inflorescence
and pedicelspedicels:
(n) the stalk of a single flower in an inflorescence, or of a grass spikelet
pilose and purplish-glandular; sepals typically 5, spreading, triangular-ovate, much larger than petals; petals typically 5, small, ovateovate:
(adj) egg-shaped in outline; generally with the broad end at or near the base
to ellipticelliptic:
(adj) in the form of an ellipse (oval)
, dark red; stamens 20-25, shorter than petals, dark red-purple.

Natural habitat

often in sphagnum-dominated ponds, fens, bogs, marshes, swamps, wet meadows prone to flooding, creek, stream and lake margins; always associated with fresh, non-brackish water

Additional comments

A monotypicmonotypic:
(adj) represented by a single example (species)
genus; Comarum palustre was previously included in Potentilla and is often offered under the synonym P. palustris (L.) Scop.

Linnaeus recognized five distinct genera whose phylogeny has since proven to be problematic (Potentilla, Comarum, Fragaria, Sibbaldia, and Tormentilla). Suggestions to group all these genera under Potentilla soon followed, leading to issues regarding monophyly. Early molecular phylogenetic analysis indicated that previously segregated genera (including Comarum) could only be included in Potentilla if an impractical taxonomic group were to be accepted (Eriksson et al, 1998). Further analysis placed Comarum in the Fragariinae clade, still within the Potentilleae but outside of Potentilla (Eriksson et al, 2003). Although the phylogeny is well-supported, Comarum palustre may still be referred to as the synonym Potentilla palustris.