FNA: Piperia unalascensis vs. Piperia

Phenology

Flowering Jun–Aug; Apr–May, lowlands of n Calif.

Habitat

Coniferous and mixed evergreen forests, generally dry sites, rarely coastal bluffs

Elevation

0–3000 m (0–9800 ft)

Distribution

AK; CA; CO; ID; MI; MT; NM; NV; OR; SD; UT; WA; WY; AB; BC; NF; ON; QC

[WildflowerSearch map]

[BONAP county map]

Temperate regions; North America (including Mexico)

[BONAP county map]

Discussion

The racemes in Piperia unalascensis are usually slender and sparsely flowered; racemes of uncommon coastal populations (including the type) are short, stout, and densely flowered. Plants of the coast ranges and the Pacific Northwest are stouter and have broader sepals and petals than do interior and montane forms. Two sympatric forms appear to be in the Sierra Nevada, differing in lip morphology and scent.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species 10 (10 in the flora).

Piperia is perhaps the most taxonomically complex orchid genus in North America. Considerable variation occurs within most species, and distinctions among taxa are often subtle. In pressed, dried specimens important characteristics that otherwise may be obvious in the field are frequently obscured. Our views on the taxonomy of the genus evolved as more extensive field and garden studies have helped us interpret geographic patterns of variation and recognize additional unifying or distinguishing characteristics.

Leaf, bract, and floral measurements in the following descriptions represent the largest dimensions on a given plant.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

1. Spur 7–18 mm; viscidia ovate to oblong.	→ 2
1. Spur 1–6 mm; viscidia broadly elliptic-ovate to rectangular-ovate.	→ 6
2. Viscidia oblong, at least 2 times as long as wide; flowers white with green or yellow-green midvein; stem base usually thickened toward tuberoid.	→ 3
2. Viscidia ovate to broadly elliptic or broadly oblong, usually less than 2 times as long as wide; flowers green; stem base uniform in diameter or attenuate toward tuberoid.	→ 4
3. Spurs of most flowers straight, horizontal; stem 0.7–4.5 mm diam.; floral fragrance clovelike.	P. transversa
3. Spurs of most flowers curved, deflexed; stem (2–3)–12 mm diam.; floral fragrance musky or pleasant, not clovelike.	elegans subsp. elegans
4. Seeds usually blackish brown; lip triangular-ovate; petals erect-spreading; stem attenuate toward tuberoid.	P. michaelii
4. Seeds pale brown to cinnamon brown; lip lanceolate to broadly triangular; petals usually strongly erect-recurved; stem basally attenuate or not.	→ 5
5. Petals falcate, ovate-attenuate, about 2 mm wide at base and 2–3 times as long; lip less than 2 times as long as wide; spur (7–)9–15(–18) mm; widespread.	P. elongata
5. Petals straight, linear, about 1 mm wide at base and 4–5 times as long; lip about 2 times as long as wide; spur 4–9 mm; not common, California.	P. leptopetala
6. Lip strongly recurved toward spur with age; flowers white or white and green; raceme rachis usually shorter than peduncle.	→ 7
6. Lip straight or upwardly curved; flowers green; raceme rachis usually at least as long as peduncle.	→ 9
7. Stem bracts usually fewer than 6; raceme ± secund; lip triangular-ovate; petals straight, white or with faint green midvein; c California to se Alaska.	P. candida
7. Stem bracts usually more than 6; raceme cylindric; lip triangular-lanceolate; petals erect, curved, green with white border; California.	→ 8
8. Petals falcate, outer white border much broader than inner; stem base attenuate toward tuberoid; flowers weakly fragrant, never cinnamonlike, diurnal; Monterey Bay area, California.	P. yadonii
8. Petals straight-sided, inner and outer white border subequal; stem base swollen; flowers strongly cinnamon-scented, nocturnal; Point Reyes, California.	elegans subsp. decurtata
9. Spur shorter than lip, 1–2.5 mm; flowers scentless; leaves grasslike, erect, less than 1 cm wide.	P. colemanii
9. Spur at least as long as lip, 2–6 mm; flowers scented, at least at night; leaves not grasslike, prostrate to erect-spreading, usually over 1 cm wide.	→ 10
10. Petals linear with slightly expanded base, about 4 times longer than wide, strongly upwardly recurved; lip narrowly lanceolate; spur attenuate, 4–9 mm; flowers with lemony scent or otherwise pleasant, not musky or honeylike.	P. leptopetala
10. Petals lanceolate to triangular-ovate, less than 3.5 times longer than wide, usually projecting to ± erect; lip triangular-ovate to lanceolate-elliptic; spur narrowly cylindric, blunt, 2–6 mm; flowers musky- or honey-scented.	→ 11
11. Mature seeds blackish brown; flowers honey-scented; raceme rachis ± length of peduncle; stem attenuate toward tuberoid; Santa Monica Mountains to n Baja California, below 1500 m.	P. cooperi
11. Mature seeds tan to cinnamon brown; flowers ± musk-scented; raceme rachis usually longer than peduncle; stem diameter uniform or increasing toward tuberoid; widespread in North America but in s California occurring only above 1500 m.	P. unalascensis