Key to the Wintergreens of California

What’s new in the key? Well, I added some information on how to identify P. dentata, P. aphylla, and P. crypta, species that are currently missing from The Jepson manual: vascular plants of California (2nd edition) treatment by Gary D. Wallace & Erich Haber. Check it out!

Genus Pyrola (Ericaceae)

Habit: Perennial subshrub, evergreen, rhizomed. Leaf: ± basal, reniform, ovate, ± round, elliptic, or obovate, ± entire to crenate or dentate, generally petioled. Inflorescence: raceme, ± erect, not 1-sided, elongate; scape smooth, glabrous, bracts generally 1–several, deltate or lanceolate; flower bract 1 per flower, < to >> pedicel. Flower: radial, ± closed or subradial or bilateral, ± open, parts in 5s, free; petals without tubercles, upper 2 generally forming hood over upturned stamens; stamens 10, filaments generally widened at base, smooth, glabrous, anther generally with tube-like constrictions subtending pores; nectary 0; ovary superior, style ± included, straight, or exserted, downcurved, stigma peltate, with 5 spreading lobes above a prominent, reflexed collar or not peltate, with 5 ± erect lobes projecting beyond a delicate, reflexed collar. Fruit: capsule, pendent; valves opening base to tip, margins fibrous. Seeds: generally 1000–5000. Species in genus: ± 30 species: generally circumboreal, high mountains of Central America, Sumatra. Etymology: (Latin: little pear, ± from leaf shape)

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1.  Flowers radial, ± closed; style ± included, straight, < 2 mm; anthers < 1.5 mm, ± without tube-like constrictions subtending pores (subg. Amelia) ….. P. minor
1′  Flowers subradial or bilateral, ± open; style exserted, downcurved, > 4 mm; anthers ≥ 2 mm, with tube-like constrictions subtending pores (subg. Pyrola)

2.  Flower bract generally >> pedicel

3.  Leaf blades generally vestigial or 0, sessile, ± appressed, ± not green, dull adaxially …..-> P. aphylla (1)
3′  Leaf blades well developed, petioled, spreading, green (chlorophyll present), shiny adaxially …..-> P. asarifolia

4.  Flower bract ± < 1.5 x pedicel; sepals 2–3.5 mm, deltate to lanceolate; leaf round to reniform, entire to ± crenate; anthers 2–3 mm …..-> subsp. asarifolia
4′  Flower bract generally > 2 x pedicel; sepals 3–5.8 (generally >> 3.5) mm, lance-oblong; leaf round to elliptic, generally minutely mucronate-dentate; anthers 2.5–3.5 mm …..-> subsp. bracteata

2′  Flower bract generally ≤ pedicel

5.  Leaf blades generally vestigial or 0, largest lanceolate to deltate, sessile, ± not green, < 1.5 cm …..-> P. aphylla (2)
5′  Leaf blades generally present, largest round to obovate, oblanceolate, or elliptic, petioled, green, generally > 1.5 cm

6.  Leaves glaucous, bluish, erect, blades variously shaped, entire to serrate, petiole ± < 1/2 length of blade …..-> P. dentata
6′  Leaves not glaucous, dark green, spreading, blades variously shaped, entire (rarely serrate), petiole ± ≥ 1/2 blade

7.  Leaf blade without white mottling on veins adaxially, round, longest generally < 2.5 cm, adaxial veins raised …..-> P. chlorantha
7′  Leaf blade with white mottling on veins adaxially, ovate to obovate to elliptic, longest generally > 2.5 cm; adaxial veins not raised

8.  Sepals > 2.2 mm; flower bract generally > 1/2 pedicel; KR, CaR, NCoRO, NCoRH .….-> P. crypta
8′  Sepals generally < 2 mm; flower bract generally ± 1/2 pedicel; NW, CaR, SN, SnFrB, SCoRO, SnBr, PR, SnJt, MP …..-> P. picta

Pyrola aphylla Sm.
Leafless wintergreen
Leaf: blade generally vestigial or 0, largest ± 1 cm, lanceolate to deltate, ± not green, occasionally with ± light-colored adaxially along veins, often hidden by leaf litter or loose substrate; petiole 0.  Inflorescence: < 6 dm including scape, often several together, flowers 7–25; flower bract 0.5–1.5 × pedicel.  Flower: bilateral, ± open; sepals generally 2–3 mm; petals 5–7.5 mm, cream-white or pink; anthers 2.8–4.5 mm; style exserted, downcurved, stigma lobes erect.  Chromosomes: 2n=46.  Ecology: Mixed conifer forest to Quercus, Arbutus, or Pinus woodland, forested serpentine areas, in deep litter and duff on hillsides of decomposed granite or loose, coarse sand.  Elevation: 500–2500 m.  Bioregional distribution:  NW, CaR, SNF, SNH, CW, SCoR, SnBr, PR, MP;  Distribution outside California:  to southwest British Columbia, Baja California.  Synonyms: Pyrola picta f. aphylla (Sm.) Camp, Thelaia aphylla (Sm.) Alef.  Note: Occasionally hybridizes with other species in sympatry and produces clones with blades expanded to ± 1 cm.  Reference: Camp 1940 Bull Torrey Bot Club 67:453–465; Haber 1987 Syst Bot 12:324–335  Flowering time: Jun–Aug

Pyrola asarifolia Michx.
Pink wintergreen
Leaf: < 10 cm, abaxially often purple, adaxially ± shiny; petiole ± = blade.  Inflorescence: < 6 dm including scape, flower number ± 10; flower bract generally > pedicel, broadly lanceolate, acuminate.  Flower: subradial to bilateral, ± open; sepals deltate to lanceolate, acute to acuminate; petals 5.3–6.7 mm pink to deep red; anthers 1.7–3.5 mm; style exserted, downcurved, stigma lobes ± erect.  Reference: Haber 1983 Syst Bot 8:277–298

Pyrola asarifolia subsp. asarifolia Michx.
Bog wintergreen
Leaf: 3–13 cm, round to reniform; entire to ± crenate; petiole ± = blade.  Inflorescence: scapes 1–3.5 dm; flower bract 1–1.5 × pedicel.  Flower: sepals 2–3.5 mm, deltate to lanceolate; anthers 2–3 mm.  Chromosomes: 2n=46.  Ecology: Common. Moist forest, swamps, bogs, streambanks;  Elevation: 30–2800 m.  Bioregional distribution: KR, CaRH, SNH, SnBr, MP;  Distribution outside California: to southern Alaska, Montana, eastern North America; eastern Asia.  Reference: Knaben & Engelskjøn 1968 Arb Univ Bergen, Mat Naturvitensk, Ser 1967:1–71; Haber 1983 Syst Bot 8:277–298  Flowering time: Jun–Jul

Pyrola asarifolia subsp. bracteata (Hook.) Haber
Long-bracted wintergreen
Leaf: 4.5–20 cm, ± round to elliptic, generally minutely mucronate-dentate; petiole ± = blade.  Inflorescence: scapes slender, 2–4.5 dm; flower bract generally > 2 × pedicel, acuminate. Flower: sepals 3–5.8 (generally >> 3.5) mm, lanceolate to lance-oblong; anthers 2.5–3.5 mm; petals 6–9 mm, broadly ovate to obovate, pink, pink-purple, or dull red; style 6–8 mm.  Ecology: Uncommon. Moist to dry forest, mixed conifer forest, coastal prairie;  Elevation: 100–2000 m. Bioregional distribution: NW, n SNH;  Distribution outside California: to southern Alaska, Montana.  Reference: Haber 1983 Syst Bot 8:277–298  Flowering time: Jun–Jul

Pyrola chlorantha Sw.
Green-flowered wintergreen
Leaf: generally present, < 4 cm; blade ± 1–2.5 cm, round to ovate, leathery, entire, adaxially dull, dark green, with veins raised; petiole ± = blade.  Inflorescence: < 3 dm including scape; flowers 1–10; flower bract < pedicel, narrowly lanceolate.  Flower: bilateral, ± open; sepals generally < 1.8 mm, deltate; petals pale green to white; anthers 2–4 mm; style exserted, downcurved, stigma lobes ± erect.  Chromosomes: 2n=46.  Ecology: Generally mixed conifer forest;  Elevation: 900–2200 m.  Bioregional distribution: Presumed extirpated but known from NCoRH, SNH (to be sought in SnBr, SNE, Dmtns);  Distribution outside California: circumboreal, North America, Eurasia.  Synonyms: Pyrola virens Schweigg.  Note: Occasionally produces clones with highly reduced leaves, appearing to be leafless.  Reference: Haber 1988 Can J Bot 66:1993–2000; Knaben & Engelskjøn 1968 Arb Univ Bergen, Mat Naturvitensk, Ser 1967:1–71  Flowering time: Jul–Aug

Pyrola crypta Jolles
Cryptic wintergreen
Leaf: present, ± 5–8 cm, with 1–many scale-like leaves between; blade 2.9–4.9 cm, elliptic to obovate, dark green, with white mottling on veins; petiole < blade.  Inflorescence: 7–14 cm including scape; flowers 7–16; flower bract ± = pedicel.  Flower: bilateral, ± open; sepals 2.2–3.4 mm, lanceolate, tips ± recurved; petals 5.3–6.5 mm; anthers 2.5–3.2 mm; style exserted, downcurved, stigma lobes erect.  Ecology: Uncommon. Moist to dry mixed conifer forests, often with granite;  Elevation: 500–1900 m.  Bioregional distribution: KR, CaR, NCoRO, NCoRH;  Distribution outside California: to Washington.  Note: May be confused with Pyrola picta.  Reference: Jolles & Wilson Taxon 63(4): 789-800.  Flowering time: Jul–Aug

Pyrola dentata Sm.
Toothed wintergreen
Leaf: generally present, glaucous, bluish; blade 2–9 cm, round, elliptic, or oblanceolate, blade base generally tapering to petiole, entire to serrate; petioles ± 1/4–1/2 length of blade.  Inflorescence: 3–13 cm, flowers 1–20; scape 5–10 cm; flower bract 2–4 mm; pedicel 3.5–9 mm.  Flower: bilateral, ± open;  sepals 1.1–2.3 mm, deltate; petals 4.1–8 mm; anthers 2.6–4 mm; style ± 5.9–8.8 mm, exserted, downcurved, stigma lobes erect.  Chromosomes: 2n=46.  Ecology: Mixed conifer forest, mixed conifer and Quercus woodland, Pinus woodland, forested serpentine and volcanic areas, hillsides of decomposed granite or loose, coarse sand or gravel near rocky outcrops;  Elevation: 55–2900 m.  Bioregional distribution: NW, CaR, SN, SnFrB, TR, PR, MP;  Distribution outside California: to southwest British Columbia, Baja California.  Synonyms: Pyrola picta subsp. dentata (Sm.) Piper; Pyrola picta var. dentata (Sm.) Dorn; Pyrola pallida Greene; Pyrola picta subsp. pallida (Greene) Andres; Pyrola picta subsp. integra (A. Gray) Piper  Note: Occasional hybridization with other species in sympatry; different morphology in northern, southern California needs study.  Reference: Haber 1987 Syst Bot 12:324–335.  Flowering time: Jun–Aug

Pyrola minor L.
Lesser wintergreen
Leaf: < 5 cm; blade round to obovate, dull green, entire to obscurely crenate; petiole ± = blade.  Inflorescence: < 2 dm including scape, flowers 3–10; flower bract > pedicel, lance-oblong, generally larger, wider at base of inflorescence.  Flower: radial, ± closed; sepals 1.5–2 mm, deltate; petals 3.5–5 mm, white to ± pink; anthers < 1 mm, anther pore width ≥ anther width, ± without tube-like constrictions subtending pores; style ± included, straight, stigma lobes spreading.  Chromosomes: 2n=46.  Ecology: Uncommon. Moist, mossy or boggy areas, high montane conifer forest;  Elevation: 2400–3000 m.  Bioregional distribution: KR, c & s SN, SnBr, SnJt, Wrn;  Distribution outside California: circumboreal, to Alaska, eastern North America, Eurasia.  Note: Primarily self fertilizing, but may hybridize in sympatry with Pyrola asarifolia, Pyrola rotundifolia.  Reference: Knaben & Engelskjøn 1968 Arb Univ Bergen, Mat Naturvitensk, Ser 1967:1–71; Haber 1984 Canad J Bot 62:1054–1061.  Flowering time: Jul–Aug

Pyrola picta Sm.
White-veined wintergreen
Leaf: blade 2.5–7 cm, ovate to obovate to elliptic, ± entire,  dark green, generally with white mottling on veins adaxially, occasionally purple abaxially; petiole 1/4 or = blade.  Inflorescence: < 3.5 dm including scape, flowers 5–25; flower bract 2–4 mm, generally ± 1/2 length of pedicel.  Flower: bilateral, ± open; sepals 1.2–2.5 mm, deltate to lanceolate; petals 5–7 mm, greenish, cream-white, or pink; anthers 2.5–3.5 mm; style 3.6–7.6 mm, exserted, downcurved; stigma lobes ± erect.  Chromosomes: 2n=46.  Ecology: Moist to dry mixed conifer forests, Pinus woodlands, volcanic areas, occasionally on decomposed granite.  Elevation: 400–2400 m.  Bioregional distribution: NW, CaR, SN, SnFrB, SCoRO, SnBr, PR, SnJt, MP;   Distribution outside California: to British Columbia, New Mexico.  Note: Occasional hybridization with other Pyrola species in sympatry (pollen, seeds sometimes abortive), occasional production of clones with highly reduced leaves, appearing leafless.  Reference: Haber 1987 Syst Bot 12:324–335.  Flowering time: Jun–Aug

Citations

Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken, editors. 2012. The Jepson manual: vascular plants of California, second edition. University of California Press, Berkeley.

Camp WH. 1940. Aphyllous forms in Pyrola. Bulletin of the Torrey Botanical Club 67: 453–465.

Haber E. 1983. Morphological variability and flavonol chemistry of the Pyrola asarifolia complex (Ericaceae) in North America. Systematic Botany 8: 277–298.

Haber E. 1984. A comparative study of Pyrola minor x Pyrola asarifolia (Ericaceae) and its parental species in North America. Canadian Journal of Botany 62: 1054–1061.

Haber E. 1987. Variability, distribution, and systematics of Pyrola picta s.1. (Ericaceae) in western North America. Systematic Botany 12: 324–335.

Haber E. 1988. Hybridization of Pyrola chlorantha (Ericaceae) in North-America. Revue Canadienne de Botanique 66: 1993–2000.

Jolles DD, Wolfe AD. 2012. Genetic differentiation and crypsis among members of the myco-heterotrophic Pyrola picta species complex (Pyroleae: Monotropoideae: Ericaceae). Systematic Botany 37: 468–477.

Jolles DD, Wilson CA. 2014. Pyrola crypta: a Pacific Northwest species belonging to the Pyrola picta species complex. Taxon 63(4): 789-800.

Knaben G, Engelskjøn T. 1968. Studies in Pyrolaceae, especially in the Pyrola rotundifolia complex. Årbok Universitetet iBergen, Mat Naturvitensk, Ser 1967: 1–71.