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)


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 rotundifoliaReference: 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: 324335.

Haber E. 1988. Hybridization of Pyrola chlorantha (Ericaceae) in North-America. Revue Canadienne de Botanique 66: 19932000.

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: 468477.

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.

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3 Replies to “Key to the Wintergreens of California”

  1. Wow! A lot of work must have gone into writing these descriptions for the key. I’m impressed! Is the new edition going to be published soon?

    1. Oh, most of the descriptions were simply modified from previous ones! I updated them, added a species, and the editors at the Jepson herbarium will ultimately help get these into the electronic version of the manual for California. Many people rely on TJM2 for up-to-date information about taxonomy and I get questions about P. aphylla pretty frequently, so I hope the key is useful.

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