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Pyrola (Ericaceae, Pyroloideae) is a genus of 20-30
species that are principally found in boreal, temperate, and arctic regions
of the Northern Hemisphere. The genus is characterized by a more or less
herbaceous habit, scapose stems with leaves clustered near the base, terminal
and symmetrically racemose inflorescences, choripetalous and actinomorphic
to slightly zygomorphic flowers, superior ovaries, declinate styles, stigmas
surrounded by a collar or ring, and capsular fruits. The delimitation
of species is frequently problematic since they are defined mostly by subtle,
but definite variations in leaf shape and size, scape bract shape, sepal
shape, anther form and color, and flower color (Haber & Cruise, 1974).
A single species, P. angustifolia, occurs in the Neotropics, and it grows in the mountains of Mexico and Guatemala.
The first comprehensive revision of Pyrola was that of Alefeld (1856). The classification of Pyrola was
revisited by Krísa (1965, 1966a, 1966b) who, in a synopsis of the
genus (1971), recognized 30 species and two subgenera, subgen. Pyrola (synonym Thelaia) and subgen. Amelia. Haber (1983,
1984, 1985, 1988), in a series of revisions of species complexes and analyses
of hybrids in the genus Pyrola, has relegated a number of Krísa's
poorly-defined species to synonymy. A world-wide monograph of the
genus nonetheless is desirable. |
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PYROLA Linnaeus, Sp. pl. 396. 1753. Pirola
Necker, Delic. gallo-belg. 557. 1768, orth. var. Pyrola Linnaeus subgen. Eupyrola Döll, Fl. Baden 2(2): 827.
1859. Lectotype designated by Britton & Brown (1913): Pyrola
rotundifolia Linnaeus.
Amelia Alefeld, Linnaea 28: 8, 25. 1856. Pyrola Linnaeus sect. Amelia (Alefeld) Hooker in Bentham
& Hooker (1876); Pyrola Linnaeus subgen. Amelia (Alefeld) Andres, Ber. Versamml. Bot.-Zool. Vereins Rheinland-Westfal.
1912: 76. 1913. Lectotype designated by Dorr (1995): Amelia minor (Linnaeus) Alefeld (=Pyrola minor Linnaeus).
Herbs or subshrubs, erect, to 3.5 dm tall
(4.4 dm in fruit), stems usually single, glabrous. Leaves alternate
or subopposite, clustered at the base in a rosette that represents several
years growth, blades slightly inrolled or
revolute, coriaceous, margin entire or crenate (rarely serrulate, the
veins ending in minute teeth). Inflorescences symmetric racemes;
scape bracts 1-4; pedicels bracteate. Flowers mostly nodding;
calyx persistent in fruit; corolla crateriform or broadly campanulate,
slightly zygomorphic, the petals concave, white, or with a creamy, greenish,
or pinkish tinge, without appendages or tubercles; stamens ±
included, clustered on the adaxial side of the flower: filaments
flattened or ribbon-like, gradually tapering to their bases, glabrous,
purple or purplish-red (?); anthers oblong, wrinkled, smooth (mucronate
at base), the tubes short, slightly expanded near filament attachment,
the pores oval or elliptic; ovary without a nectariferous disc;
style declinate, exserted, the apex turned upward; stigma slightly
expanded, subtended by an inconspicuous collar or ring below the 5 papillate
stigmatic crests or lobes. Fruit a depressed-globose capsule, dark
brown, pendant, borne on a recurved pedicel, dehiscence incomplete, the
margins of the valves cobwebby; seeds light golden-brown, the testa
pitted. Chromosome numbers: n=23, 46.
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Key to Neotropical Species Back to Top
Pyrola angustifolia
This is a version of the taxonomic
treatment of Pyrola (Ericaceae:
Pyroloideae) by Laurence J. Dorr, modified from "Ericaceae--Part II. The
Superior-Ovaried Genera (Monotropoideae, Pyroloideae, Rhododendroideae,
and Vaccinioideae p.p.)." The full treatment including specimen citations
may be see in Flora Neotropica Monograph 66: 49-53 (Dorr, 1995d). This on-line synthesis is published with
permission of The New York Botanical Garden and Laurence J. Dorr.
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