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owl's-clover, owl-clover

narrow-leaf owl-clover, thin-leaf owl's-clover, thin-leaf owl-clover

Habit Herbs, annual; hemiparasitic. Annuals 8–35 cm.
Stems

erect or ascending, not fleshy, glabrous or hairy.

erect or ascending, pilose and puberulent.

Leaves

cauline, alternate;

petiole absent;

blade not fleshy, not leathery, margins entire or 3–7-lobed.

10–50 mm;

blade: proximal margins entire, distal 3–7-lobed.

Inflorescences

terminal, spikes or racemes;

bracts present.

racemes, 2–6 cm;

bracts 10–20 mm, margins 3–5-lobed in proximal 1/2, proximal not resembling distal leaves, midlobe purple-pink distally, ovate, 4–6 mm wide, apex obtuse, cuspidate, lateral lobes narrowly triangular.

Pedicels

absent or present;

bracteoles absent.

1–2 mm.

Flowers

sepals 4, calyx symmetric, tubular, lobes triangular;

petals 5, corolla purple-pink, yellow, or white, strongly bilabiate, club-shaped, often gibbous at base of abaxial lip, abaxial lobes 0 or 3, adaxial 2, adaxial lip galeate, rounded at apex, sometimes obscurely so, opening downward;

stamens 4, didynamous, filaments glabrous or hairy;

staminode 0;

ovary 2-locular, placentation axile;

stigma linear, not expanded at apex.

calyx 8–12 mm;

corolla 14–20 mm, equal to or slightly longer than bracts, abaxial lip inflated, lobes 3, triangular, adaxial lip purple-pink, 5 mm, 1 mm longer than abaxial, puberulent, tip notably hooked, not bearded.

Capsules

dehiscence loculicidal.

6–7 mm, apex acute.

Seeds

5–35, light to dark brown or yellow, ovoid to reniform or oblong, wings absent.

15–20, dark brown, ovoid to reniform, 1–1.5 mm, shallowly reticulate, not ridged.

x

= 7.

2n

= 28.

Orthocarpus

Orthocarpus tenuifolius

Phenology Flowering May–Aug.
Habitat Moist fields, grasslands, rocky slopes.
Elevation (300–)600–2500 m. ((1000–)2000–8200 ft.)
Distribution
from USDA
w North America
[BONAP county map]
from FNA
ID; MT; OR; WA; WY; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Species 9 (9 in the flora).

Orthocarpus is related to Cordylanthus and can be distinguished by its four-lobed, tubular calyces (D. C. Tank et al. 2009). Some species placed traditionally in Orthocarpus were transferred to Castilleja and Triphysaria by T. I. Chuang and L. R. Heckard (1991).

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

Orthocarpus tenuifolius is one of the plants first collected by Meriwether Lewis during the Corps of Discovery Expedition.

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

Key
1. Bract margins 5–7-lobed; pedicels 2–3 mm; corollas: adaxial lips bearded at tip.
O. barbatus
1. Bract margins entire or 3(–5)-lobed; pedicels 0–2 mm; corollas: adaxial lips not bearded at tip.
→ 2
2. Bracts: midlobes ovate or obovate, 4–10 mm wide, apices obtuse, cuspidate.
→ 3
3. Corollas: adaxial lips not hooked at tip.
O. cuspidatus
3. Corollas: adaxial lips notably hooked at tip.
→ 4
4. Corollas 25–30 mm, adaxial lips glabrous, abaxial lobes rounded.
O. pachystachyus
4. Corollas 10–20 mm, adaxial lips puberulent, abaxial lobes triangular.
→ 5
5. Distal leaf margins entire; calyces 5–7 mm; capsules 4–5 mm, apices retuse.
O. imbricatus
5. Distal leaf margins 3–7 lobed; calyces 8–12 mm; capsules 6–7 mm, apices acute.
O. tenuifolius
2. Bracts: midlobes triangular, 0.7–4 mm wide, apices acute or acuminate, not cuspidate.
→ 6
6. Corollas: adaxial lips golden yellow, tips minutely hooked.
O. luteus
6. Corollas: adaxial lips yellow or purple-pink to white, tips notably hooked.
→ 7
7. Distal leaf margins entire; seeds 3–6; corollas: abaxial lips with triangular lobes.
O. tolmiei
7. Distal leaf margins 3-lobed; seeds 10–26; corollas: abaxial lips with lobes 0.
→ 8
8. Bracts: midlobes 3–4 mm wide, lateral lobes narrowly triangular; capsule apices retuse; seeds 10–15.
O. bracteosus
8. Bracts: midlobes 1–2 mm wide, lateral lobes linear; capsule apices cuspidate; seeds 18–26.
O. purpureoalbus
Source FNA vol. 17, p. 680. Author: Kerry A. Barringer. FNA vol. 17, p. 683.
Parent taxa Orobanchaceae Orobanchaceae > Orthocarpus
Sibling taxa
O. barbatus, O. bracteosus, O. cuspidatus, O. imbricatus, O. luteus, O. pachystachyus, O. purpureoalbus, O. tolmiei
Subordinate taxa
O. barbatus, O. bracteosus, O. cuspidatus, O. imbricatus, O. luteus, O. pachystachyus, O. purpureoalbus, O. tenuifolius, O. tolmiei
Synonyms Bartsia tenuifolia
Name authority Nuttall: Gen. N. Amer. Pl. 2: 56. (1818) (Pursh) Bentham: Scroph. Ind., 12. (1835)
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