Key to Heuchera

View taxon page for Heuchera

(For a list of species in Heuchera, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Styles and generally all stamens 

included 

Not protruding out of surrounding structure(s) (e.g., stamens included in corolla).

in full flower

2. Petals generally 0; inflorescence narrow, spike-like ..... H. cylindrica

2' Petals present, ± conspicuous; inflorescence more open, 

panicle 

1. In flowering plants excluding Asteraceae, Cyperaceae, Poaceae, and some other groups, a branched inflorescence in which the basal or lateral flowers (or some of them) open before the terminal or central flowers on any axis. 2. In Asteraceae, Cyperaceae, Poaceae, and some other groups, a panicle-like inflorescence is one in which at least some of the inflorescence units (e.g., heads in Asteraceae; spikelets in Cyperaceae and Poaceae), instead of individual flowers, are attached (stalked or unstalked) to branches and not directly to the main axis of the inflorescence and in which floral development may or may not proceed as in 1.

or raceme-like

3. Hypanthium + calyx 2–3(4.2) mm, 

radial 

Divisible into mirror-image halves in three or more ways.

; calyx 

lobes 

1. A major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. The free tips of otherwise fused structures, such as sepals or petals; larger than teeth.

equal, cream to ± yellow, tips pink to ± green ..... H. parvifolia

3' Hypanthium + calyx generally > 3.5 mm, ± 

bilateral 

Divisible into mirror-image halves in only one way.

; calyx lobes ± unequal, light pink to red-purple, tips green or not (Heuchera caespitosa complex)

4. Inflorescence glands nearly 

sessile 

Without a petiole, peduncle, pedicel, or other kind of stalk.

, stalk ± = gland; 

leaf 

Organ arising from a stem, generally composed of a stalk (petiole) and a flat, expanded, green, photosynthetic area (blade); distinguished from a leaflet by the presence in its axil of a bud, branch, thorn, or flower; sometimes with lateral, basal appendages (stipules); either simple (toothed, lobed, or dissected but not divided into leaflets) or compound (divided into leaflets).

 

blade 

Expanded portion of a leaf, petal, or other structure, generally flat but sometimes rolled, cylindric, wavy, or cupped.

generally < 15 mm, generally broadly 

ovate 

Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf.

, lobed ± 1/2 to base ..... H. abramsii

4' Inflorescence glands nearly sessile and long-stalked, stalk >> gland; leaf blade generally > 15 mm, generally round to 

reniform 

Kidney-shaped; often pertaining to a leaf in which the blade base on both sides of the petiole is rounded and concave.

, lobed 1/4–1/3 to base

5. Stamens generally < 1/2 calyx lobes; part of 

hypanthium 

Structure generally in the shape of a tube, cup, or bowl, derived from the fused lower portions of the perianth and stamens, from which these parts seem to arise, and to which the ovary wall is fused in an inferior ovary (to which the ovary wall is partially fused in a half-inferior ovary; from which the ovary is free in a superior ovary).

 free from ovary ± 0.7 mm on short side, ± 1.5 mm on long side – PR (San Diego Co.) ..... H. brevistaminea

5' Stamens ± = calyx lobes; part of hypanthium free from ovary > 0.8 mm on short side, > 1.8 mm on long side

6. Calyx lobes all well developed ..... H. caespitosa

6' Calyx lobes on long side of hypanthium minute – PR ..... H. hirsutissima

1' Styles and stamens 

exserted 

Protruding out of surrounding structure(s) (e.g., stamens exserted from corolla).

in full flower

7. Flower ± bilateral; calyx lobes ± equal or not; part of hypanthium fused to ovary ± = long side of free part

8. Petals 2–3 mm, > 0.3 mm wide, oblanceolate, unequal; hypanthium strongly 

oblique 

Having unequal sides or an asymmetric base.

..... H. parishii

8' Petals 3–6 mm, generally << 0.3 mm wide, thread-like to narrowly oblanceolate, equal; hypanthium slightly oblique ..... H. rubescens

7' Flower ± radial; calyx lobes ± equal; part of hypanthium fused to ovary generally > free part

9. Styles 2–4 mm, exserted; hypanthium broadly obconic, base 

tapered 

Gradually (not abruptly) narrower or smaller at base or tip.

; inflorescence generally open

10. Hypanthium + calyx 3.5–4.5 mm; leaf blade 6–18 cm wide; n ChI ..... H. maxima

10' Hypanthium + calyx 1.5–3(5) mm; leaf blade 2–10 cm wide; mainland ..... H. micrantha

9' Styles generally <= 1.8 mm, barely exserted; hypanthium bell-shaped, base 

truncate 

Abruptly (not gradually) narrower or smaller at base or tip, as if cut straight across or nearly so.

; inflorescence ± dense or open

11. Leaf blade generally round, base ± truncate; 

petiole 

Leaf stalk, connecting leaf blade to stem; sometimes more or less indistinct.

2–5 cm, hairs short, stiff; >= 1500 m ..... H. merriamii

11' Leaf blade generally ovate, base 

cordate 

Heart-shaped; often pertaining to a leaf in which the blade base on both sides of the petiole is rounded and convex.

; petiole 7–20 cm, hairs long, soft; < 500 m ..... H. pilosissima

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