Diplacus rutilus

(A. L. Grant) McMinn

Madroño 11: 83. 1951.

Common names: Santa Susana bush monkeyflower
Endemic
Basionym: Mimulus longiflorus var. rutilus A. L. Grant Ann. Missouri Bot. Gard. 11: 333. 1925
Synonyms: Diplacus longiflorus var. rutilus (A. L. Grant) McMinn
Treatment appears in FNA Volume 17. Treatment on page 451. Mentioned on page 427, 452.

Subshrubs. Stems erect, 300–1000 (–2000) mm, glandular-puberulent and short-villous. Leaves usually cauline, relatively even-sized; petiole absent; blade elliptic to lanceolate, elliptic-lanceolate, or elliptic-oblanceolate, 25–65 (–80) × 4–15 (–25) mm, margins entire or serrate, revolute, apex acute to obtuse, abaxial surfaces densely hairy, hairs branched, adaxial glabrescent. Pedicels 5–16 mm in fruit. Flowers 2 per node, chasmogamous. Calyces not inflated in fruit, 22–32 mm, glandular-puberulent and short glandular-villous to hirsute-villous, tube slightly dilated distally, lobes unequal, apex acute, ribs green, intercostal areas light green. Corollas red to orange-red, throat whitish at least on floor, palate ridges orange or white with orange crest, tube-throat 34–45 mm, limb (25–) 28–40 mm diam., bilabiate, lobes oblong, apex of adaxial 2 each shallowly, asymmetrically incised. Anthers included, glabrous. Styles minutely glandular. Stigmas included, lobes equal. Capsules 18–28 mm.


Phenology: Flowering Mar–Jun.
Habitat: Chaparral.
Elevation: 400–600 m.

Discussion

H. E. McMinn (1951), M. C. Tulig and G. L Nesom (2012), and Nesom (2013c) treated Diplacus rutilus at specific rank, but P. A. Munz and D. D. Keck (1973) followed the original assessment of A. L. Grant (1924) in treating it as a variety of the light orange- to pale yellow-orange-flowered D. longiflorus, while R. M. Beeks (1962) and D. M. Thompson (2005) regarded this taxon as only a variant of D. longiflorus, without formal rank. It is maintained here as a distinct, red-flowered species localized in Los Angeles County, California. Diplacus rutilus occurs in pockets in a strip from Whittier and Pomona through North Pasadena westward to near the Ventura County line (the Santa Susana area being the type locality), a distance of almost 60 miles.

Very few of these red-flowered collections can be separated in any feature except corolla color from typical Diplacus longiflorus. Red corollas have not been observed in D. longiflorus outside of Los Angeles County, and D. rutilus might be interpreted as reflecting local introgression in this area from D. puniceus, but the distinctive and tightly coherent geographical distribution of these red-flowered plants and their apparent absence elsewhere in the area where D. ×australis occurs suggest that the origin of D. rutilus is different from that of the highly variable D. ×australis.

Selected References

None.

Lower Taxa

None.
... more about "Diplacus rutilus"
Incised (?) +, Acute (?) +  and Obtuse (?) +
Guy L. Nesom +  and Melissa C. Tulig +
(A. L. Grant) McMinn +
Mimulus longiflorus var. rutilus +
6.5 cm65 mm <br />0.065 m <br /> (8 cm80 mm <br />0.08 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (6.5 cm65 mm <br />0.065 m <br />) +
elliptic;lanceolate elliptic-lanceolate or elliptic-oblanceolate +
? (?) +, ? (?) +  and ? (?) +
4mm;15mm +
glandular-villous +  and hirsute-villous +
not inflated +
2.2 cm22 mm <br />0.022 m <br /> (3.2 cm32 mm <br />0.032 m <br />) +
1.8 cm18 mm <br />0.018 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
Santa Susana bush monkeyflower +
not +, rarely radially symmetric +  and weakly strongly bilabiate +
red;orange-red +
400–600 m. +
hairy +  and glabrous +
reflexed;nodding;erect +
reduced +
compressed;asymmetrically ovoid;lanceoloid or nearly cylindric +
Chaparral. +
alternate +, opposite +, rosulate +  and subrosulate +
persistent +  and deciduous +
equal-sized +
2.8 cm28 mm <br />0.028 m <br /> (4 cm40 mm <br />0.04 m <br />) +
unequal +
palmate +  and subpinnate +
serrate +  and entire +
toothed +  and subentire or entire plane or revolute +
wing-angled +  and angled +
basal +  and superior +
tenuinucellate +  and unitegmic +
orthotropous +  and anatropous +
white +  and orange +
rarely more or less equal to or slightly longer +
0.5 cm5 mm <br />0.005 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
Flowering Mar–Jun. +
flattened +, ovoid +  and oblong +
deciduous +
30 cm300 mm <br />0.3 m <br /> (100 cm1,000 mm <br />1 m <br />) +
Diplacus longiflorus var. rutilus +
Diplacus rutilus +
Diplacus +
species +
3.4 cm34 mm <br />0.034 m <br /> (4.5 cm45 mm <br />0.045 m <br />) +
dilated +
perennial +  and annual +
10 +, 9 +  and 8 +