Comarum

Linnaeus

Sp. Pl. 1: 502. 1753.

,

Gen. Pl. ed. 5, 220. 1754.

Common names: Marshlocks
Etymology: Greek komaros, strawberry-tree (Arbutus unedo Linnaeus), alluding to similarity of fruit
Synonyms: Potentilla sect. Comarum (Linnaeus) Tausch Potentilla subg. Comarum (Linnaeus) Syme
Treatment appears in FNA Volume 9. Treatment on page 300. Mentioned on page 119, 120, 122, 124, 274, 301, 304.
 TaxonIllustrator 
FNA9 P24 Comarum palustre.jpegComarum palustre
Alchemilla filicaulis subsp. vestita
Aphanes occidentalis
Marjorie C. Leggitt
Marjorie C. Leggitt
Marjorie C. Leggitt

Herbs, perennial, 1–6 dm; stoloniferous and rhizomatous. Stems 1–several, decumbent to ascending aerial stems arising from horizontal ground-level stems, horizontal stems often rooting at nodes, sometimes floating, aerial stems glabrous proximally, finely appressed-hairy and often purplish-glandular distally. Leaves usually marcescent, cauline, alternate, odd-pinnate to subpalmate; stipules marcescent, partially to completely adnate to base of petiole, linear-lanceolate to elliptic-ovate, usually entire, sometimes serrate apically; petiole present, marcescent; blade ± cordate in outline, 2–15 cm, foliaceous, leaflets (3–) 5–7, lanceolate or oblanceolate to elliptic or obovate, margins flat, crenate to deeply serrate throughout or apically, venation pinnate, surfaces glabrous or finely appressed hairy. Inflorescences terminal, 1–10-flowered, flowers solitary or loosely cymose, hairy and often purplish-glandular; bracts present, leafy, smaller distally; bracteoles absent. Pedicels present, straight or nearly so. Flowers 1–3 cm diam.; epicalyx bractlets 5; hypanthium slightly cupulate, 1–2 × (3–) 4–8 mm, villous; sepals 5, spreading to reflexed, broadly ovate; petals 5, deep red to purple, rarely pink, ovate to spatulate, shorter than sepals; stamens (15–) 20–25 (–30), shorter than or equal to petals, filaments filiform, not flattened, glabrous, thecae solitary, horseshoe-shaped, rimming broad connective, dehiscing by continuous, narrow, marginal slit; torus hemispheric; carpels 30–100, glabrous, styles lateral to subbasal, filiform; ovule 1. Fruits aggregated achenes, individually deciduous (sometimes tardily so), 30–100, obliquely ovoid, (1–) 1.3–1.6 mm, glabrous; torus enlarged, spongy, not fleshy, hairy; hypanthium persistent; sepals persistent, reflexed; styles persistent, jointed. x = 14.

Distribution

North America, Eurasia

Discussion

Species 1.

In North America, Comarum differs from Potentilla by its strikingly deep red to purple petals that are shorter than the sepals and its generally sprawling habit with rooting nodes in distinctly wet habitats. The dark reddish or purplish color generally infuses other floral parts (calyces, anthers, styles). Petals in Potentilla sect. Rubrae (Rydberg) O. Stevens are similarly colored but more or less obcordate and longer than the sepals, and the plants are otherwise typical of that genus in habit, habitat, and palmate leaves.

The fruiting structure of Comarum is intermediate between that of Fragaria and those of most other Potentilleae. As in Fragaria, the torus becomes enlarged and spongy (but not fleshy) in fruit, albeit completely covered by ultimately deciduous achenes. As supported by molecular data (T. Eriksson et al. 1998, 2003), Comarum is more closely related to Fragaria than to Potentilla in the strict sense. It will hybridize with members of Fragaria (J. R. Ellis 1962), giving rise to commercially available pink-flowered strawberries.

This treatment follows J. Soják (2008) in treating Comarum as monospecific; the other species sometimes placed in this genus is Farinopsis salesoviana (Stephan) Chrtek & Soják.

Selected References

None.

Lower Taxa

"thin" is not a number.

... more about "Comarum"
Barbara Ertter +  and James L. Reveal +
Linnaeus +
compound +  and simple +
opposite +  and alternate +
cordate +
2 cm20 mm <br />0.02 m <br /> (15 cm150 mm <br />0.15 m <br />) +
coriaceous +
smaller +
free +  and distinct +
odd-pinnate +  and subpalmate +
Marshlocks +
North America +  and Eurasia +
not +  and aggregated +
Greek komaros, strawberry-tree (Arbutus unedo Linnaeus), alluding to similarity of fruit +
not flattened +  and filiform +
cymose +  and solitary +
1 cm10 mm <br />0.01 m <br /> (3 cm30 mm <br />0.03 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
0.1 cm1 mm <br />0.001 m <br /> (0.13 cm1.3 mm <br />0.0013 m <br />) +
deciduous +
0.13 cm1.3 mm <br />0.0013 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
crassinucellate +
opposite +  and alternate +
marcescent +
deciduous +  and persistent +
oblanceolate +  and elliptic or obovate +
pinnate +  and serrate +
crenate to deeply +
inferior +  and superior +
clustered +, biseriate +  and superposed +
nearly +  and straight +
0 (?) +  and 4 (?) +
pink +, red +  and purple +
free +  and distinct +
ovate;spatulate +
adnate +, free +, connate +  and distinct +
Sp. Pl. +  and Gen. Pl. ed. +
1753 +  and 1754 +
not arillate +
persistent +
free +  and distinct +
reflexed +  and spreading +
free +  and distinct +
horizontal +, arising +  and decumbent to ascending +
appressed-hairy;glabrous +
1 +  and several +
palmate +  and pinnate +
serrate +  and entire +
linear-lanceolate;elliptic-ovate +
persistent +
distinct +
lateral +  and subbasal +
filiform +
hairy +, appressed +  and glabrous +
Potentilla sect. Comarum +  and Potentilla subg. Comarum +
Comarum +
Rosaceae tribe Potentilleae +
horseshoe--shaped +
inconspicuous +
hemispheric +
enlarged +
not fleshy +  and spongy +
rhizomatous +  and stoloniferous +