Tiarella
Tiarella trifoliata
and, coolwort, false mitrewort, foam-flower, laceflower, Latin tiara, sugar-scoop, tiarelle, turban
cut-leaf foamflower (var. laciniata), foamflower, lace flower, one-leaf foamflower (var. unifoliata), sugar-scoop, three-leaf foam-flower, three-leaf foamflower (var. trifoliata)
erect, usually leafless, rarely with 1–2 leafy bracts, 10–70 cm, short to long glandular-stipitate.
10–70 cm
in basal rosette and, sometimes, cauline, simple or 3-foliolate;
stipules present;
petiole short to long stipitate-glandular (hairs usually denser distally, gland-tipped);
blade cordate or broadly ovate, lobed, base cordate, margins crenate to dentate, apex acute, abaxial surface stipitate-glandular along veins, adaxial surface stipitate-glandular, sometimes appressed, hairs uniformly scattered;
venation palmate.
racemes (sometimes with paniculate branches at base) or panicles, terminal from axillary buds in rosette, 15–70-flowered, bracteate.
radially symmetric or somewhat bilaterally symmetric;
hypanthium barely adnate to ovary proximally, 0.2–0.9 mm free from ovary, white or pinkish, (campanulate);
sepals 5, whitish or pinkish, (ovate to lanceolate, apex acute or obtuse, glandular-stipitate abaxially, glabrous adaxially);
petals 5, white or pinkish to purplish;
nectary disc absent or inconspicuous;
stamens 10;
filaments linear;
ovary superior, 1-locular, carpels connate, unequal;
placentation parietal;
styles 2, (tapering);
stigmas 2.
2-winged (beaked), unequally valvate, abaxial carpel 1.5–2 times longer than adaxial carpel, (papery, each wing 5–10-veined).
black, shiny, ellipsoid or ovoid, (base truncate), puncticulate; (funicular appendage absent).
= 7.
Tiarella
Tiarella trifoliata
Species 3 (2 in the flora).
Intergeneric hybrids between Tiarella cordifolia and species of Heuchera and Mitella have been documented. Tiarella is placed within the Heuchera group of the Saxifragaceae. Based on cpDNA and other cytological traits, this is one of the best-defined groups of the Saxifragaceae. Chloroplast DNA restriction site data for the Heuchera group suggest the group as being paraphyletic. Tiarella cordifolia is known from eastern North America and T. trifoliata is known from western North America. Tiarella polyphylla D. Don occurs in Asia in the Himalayas through western and central China to Japan and Taiwan. Tiarella is used as a diuretic as well as for suppression of urine production and in treating kidney stones.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 3 (3 in the flora).
Varieties of Tiarella trifoliata have overlapping ranges and differ from each other in leaf form and marginal dissection. Their floral features are stable throughout. They were previously suspected of hybridizing when sympatric. They are differentiated along elevational gradients and often remain distinct in sympatric populations.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Inflorescences racemes; leaves simple; cauline leaves absent or 1; petals oblanceolate to elliptic, apex 3-toothed; e North America. | T. cordifolia |
1. Inflorescences panicles; leaves simple or trifoliolate; cauline leaves 1-5; petals linear or subulate, apex attenuate; w North America. | T. trifoliata |
1. Basal leaves usually simple; cauline leaves rarely trifoliolate, shallowly to deeply lobed, leaflets sessile. | var. unifoliata |
1. Basal leaves 3-foliolate; cauline leaves 3-foliolate; leaflets deeply lobed, petiolulate | → 2 |
2. Leaflet lobes to 1/2 length of leaflet, distal segments not laciniate. | var. trifoliata |
2. Leaflet lobes more than 1/2 length of leaflet, distal segments laciniate. | var. laciniata |
- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
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- Encyclopedia of Life
- Wikipedia
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