1.
Tiarella cordifolia
Linnaeus, Sp. Pl. 1: 405. 1753.
Heart-leaf foamflower, tiarelle cordifoliée
Tiarella cordifolia
var.
austrina
Lakela;
T. cordifolia
var
. bracteata
Farwell;
T. cordifolia
subsp
. collina
Wherry;
T. macrophylla
Small;
T. wherryi
Lakela
Flowering stems
15-40 cm.
Leaves
simple; cauline leaves absent or 1; petiole 0.2-2 dm; blade 3-13 × 3-10 cm.
Inflorescences
racemes, 15-50-flowered, 4-40 × 1-2 cm.
Pedicels
subtended by finely dissected bracts, 0.1-0.8 cm, glandular-stipitate.
Flowers:
hypanthium campanulate, 3-6 mm, glandular-stipitate; perianth radially symmetric; sepals spreading at anthesis, reflexed in fruit, 1.5-3.5 × 0.5-1 mm; petals caducous, spreading, oblanceolate to elliptic, unlobed, 0.6-1 × 3-4.5 mm, base clawed, apex 3-toothed; stamens equal, 2-6 mm; anthers oval, 0.3-0.5 mm.
Capsules
0.5-1.1 cm.
Seeds
4-15, ellipsoid, 0.9-1 × 0.4-0.7 mm.
2
n
= 14.
Flowering Mar-Jul; fruiting Apr-Sep. Open and shady, dry to swampy deciduous woods, along streams; 40-800 m; N.B., N.S., Ont., Que.; Ala., Conn., Ga., Ky., Maine, Md., Mass., Mich., Minn., Miss., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.
Tiarella macrophylla
was described from Tyron Mountain, North Carolina; the specimen consists of basal leaves of
Heuchera villosa
and racemes of
T. cordifolia
.
Tiarella wherryi
and
T. cordifolia
have been differentiated primarily on the basis of lack of stolons in
T. wherryi
. Such plants grow in mixed populations and it has been impossible to differentiate taxa on the basis of herbarium specimens. It is also thought that the differences between the taxa might be a result of altitudinal variation in habitat. Attempts by Lakela to distinguish var.
cordifolia
and var.
austrina
on the basis of leaf dimensions and marginal dentation have been thwarted by continuous variation in these characteristics.
