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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

MICRANTHES SAXIFRAGE

Michael S. Park


Plant generally ± hairy, often glandular; caudex or rhizome generally not woody, generally scaly. Leaf: basal (cauline); blade linear to (ob)ovate or ± round, base tapered to reniform, margin entire or toothed. Inflorescence: flowers few to many; bracts scale-like. Flower: generally radial; hypanthium free or ± fused to ovary; petals 5, white, sometimes with yellow spots at base; stamens 10, filaments flat or variously inflated; pistils 1 (chambers 2, placentas 2, axile or occasionally proximally axile and distally marginal) or 2, ovary superior to ± inferior (sometimes more superior in fruit), styles free throughout. Fruit: capsule or 2 follicles.
± 80 species: North America, Eurasia, South America, especially cool temperate northern hemisphere. (Latin: small flower) [Elvander 1984 Syst Bot Monogr 3:1–44] Intermediates common between Micranthes integrifolia, Micranthes nidifica, Micranthes fragosa, Micranthes aprica; some may be vegetatively reproducing, sterile hybrids. Study needed.
Unabridged references: [Small & Rydberg 1905 N Am Fl 22:132–150]

Key to Micranthes

1. Leaves cauline on ± trailing stem — blade entire; flowers in head-like cluster ..... M. tolmiei

1' Leaves basal (bracts occasionally leaf-like)

2. Proximal flowers replaced by bulblets; flowers ± bilateral, 3 petals broader than other 2

3. Base of all petals ± 2-spotted; leaf blade linear-elliptic, margin ± entire or with minute teeth distally ..... M. bryophora

3' Base of only 3 broad petals (rarely all) ± 2-spotted; leaf blade obovate, teeth generally coarse ..... M. ferruginea

2' Inflorescence bulblets 0; flowers radial, petals ± equal

4. Filaments inflated distally; petal spots 2

5. Leaf blade ovate to elliptic, base truncate to tapered; ovaries fused only at base ..... M. marshallii

5' Leaf blade ± round, base cordate to reniform; ovaries fused throughout — fruit tip purple, base yellow-banded ..... M. odontoloma

4' Filaments inflated proximally, or ± flat and not inflated; petal spots 0

6. Filaments inflated proximally; ovary superior in flower and fruit ..... M. howellii

6' Filaments not inflated proximally, ± flat, narrowed at tip; ovary ± inferior to 1/2-inferior in flower, superior in fruit

7. Plant generally > 4 dm; leaf blade linear to oblanceolate, generally > 10 cm, long-tapered to an indistinct petiole; bogs, marshes, lake margins ..... M. oregana

7' Plant <= 3.5 dm; leaf blade elliptic, obovate, ovate, or triangular, generally < 10 cm, short-tapered to a distinct petiole; not in bogs, marshes or lake margins

8. Leaf blade shallowly toothed; inflorescence ± open, often 1-sided; flowers not clustered to loosely clustered; anthers purple to red (orange); petals ± 2 × sepals; styles on fruit generally > 1.5 mm ..... M. californica

8' Leaf blade ± entire to minutely toothed; inflorescence not 1-sided; flowers loosely to densely clustered; anthers generally yellow to orange; petals < 1.7 × sepals; styles on fruit generally < 1 mm

9. Petals 1–2 mm; sepals ± reflexed ..... M. nidifica

9' Petals generally > 2 mm; sepals generally ± erect to spreading (except Micranthes fragosa)

10. Pedicels ± glabrous to sparsely glandular; generally 1 head-like cluster of flowers at tip of inflorescence, sometimes with 1 or 2 smaller clusters on nearby short lateral branches; moist, sandy and gravelly montane to subalpine habitats >= 1600 m elevation ..... M. aprica

10' Pedicels densely glandular; lateral branches of inflorescence many, each with a terminal cluster of flowers; moist meadows, rocky slopes and outcrops

11. Lateral branches of inflorescence spreading to ascending; inflorescence cluster at tip of main axis open to ± congested, hemispheric to ± flat-topped; sepals ± reflexed to spreading ..... M. fragosa

11' Lateral branches of inflorescence ascending to erect; inflorescence cluster at tip of main axis dense, conical to cylindric; sepals ± erect to ascending ..... M. integrifolia

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Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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