Navarretia aeroides L.A.Johnson & D.Gowen, 2017

Johnson, Leigh A. & Gowen, David, 2017, Ex uno, multis: taxonomic revision in Navarretia divaricata (Polemoniaceae) and the recognition of four additional cryptic or near-cryptic species, PhytoKeys 91, pp. 39-83 : 56-61

Navarretia aeroides L.A.Johnson & D.Gowen sp. nov. Figs 4 , 6

Type.

United States of America. California: Calaveras County, west of Avery, at the end of a short forest service road off of Avery Sheep Ranch Road , 38.19488°N, 120.39969°W, 3695 ft, 17 June 2015, D. Gowen, 1303 (holotype BRY! [BRY-627257]; isotypes JEPS! RSA!).

Diagnosis.

A species similar to Navarretia vividior , but distinguished by being diploid, rather than allotetraploid, and being less robust in all respects; N. aeroides has smaller inflorescence heads that are conspicuously stipitate-glandular throughout (sometimes inconspicuously villous proximally), thinner branches, tends toward smaller corollas, and has stem trichomes mostly 0.5mm or less rather than mostly ± 1 mm.

Description.

Taprooted annual herbs to 9(-12) cm tall and 15(-22) cm wide, sometimes larger, often wider than tall. Primary stem erect, terminating in an inflorescence head 1-2(-4) cm above the cotyledons; generally greatly exceeded by secondary stems, with tertiary, and quaternary stems present on larger plants; higher order branches arise from axils of proximal inflorescence bracts, axils of leaves subtending the primary head, or less commonly, leaves within 1 cm of an inflorescence head; branches ascending to spreading and ± leafless, except for leaves subtending higher order branches or within 1 cm of a head; stem and branches reddish-brown, glandular-pubescent or sparingly so, the trichomes mostly less than 0.5 mm long; distal-most branches filiform, generally no more than 0.3 mm in diameter. Cotyledons two, linear, entire, united at base. Leaves somewhat finely stipitate-glandular proximally, less so distally; leaves at the lowermost nodes opposite, linear-filiform, and widened at the point of stem attachment, the proximal nodes often congested with overlapping leaf bases. More distal leaves alternate, entire, or more commonly with 1-3(-5) paired or unpaired linear lateral lobes 1-8 mm long attached along the proximal 3-5(-15) mm of the leaf, with an elongated, linear terminal segment. Inflorescences head-like, generally ≤ 10 mm diameter (exclusive of bract tips; ~15 mm with bract tips), mostly less than 10-flowered, sometimes more, ± conspicuously glandular. Inflorescence bracts <10(-12) mm long, ± palmatifid to subpalmatifid; outermost 1-2 bracts with a short achlorophyllous base and 2-3 pairs of lateral lobes flanking an elongate terminal lobe, the distal pair of lateral lobes sometimes shorter and reflexed somewhat out of plane relative to the other lobes; bract bases become larger and clasping centripetally with lateral lobes reduced to a single pair departing from near the apex of the bract base flanking the central terminal lobe, all bract lobes chlorophyllous, entire, long tapering acute. Bracts sparsely glandular-villous abaxially, more densely glandular-villous adaxially and proximally along the lobes just above the rachis, with the stipe of each gland diminishing in length toward the bract tips. Flowers actinomorphic, calyces mostly 4.0-6.0(-8.5) mm long, tube ~ 1.3-2.2-(2.5) mm; costae entire, long tapering acute, strongly unequal to subequal with typically two costae longer than the other three; costae narrowing proximally, the shorter ones narrower at base than the intercostal membrane and the longer ones subequal with the membrane; calyx tube achlorophyllous, glandular-puberulent on the intercostal membrane and proximal costae, gland stipes lengthen on the costae at the junction with the intercostal membrane, diminishing in length toward the chlorophyllous costae tips; intercostal membrane v-shaped at sinus. Corolla generally ± equal to the calyx costae at anthesis but exceeding the calyx as fruit matures, narrowly funnelform, glabrous, 4.2-6.0 mm long, lobes 0.75-1.3 mm long × 0.5-0.9(-1.0) mm wide, tube white, transitioning to a bluish throat and lobes in some populations (drying bluish purple, with the distal tube showing hints of magenta or somewhat brownish) or remaining white in others (drying with white or light blue lobes and throat with brownish or magenta distal tube); tube base expanding and investing the fruit apex. Stamen filaments unequal, 0.2-0.55 mm long, inserted unequally 0.4-0.9 mm below corolla sinuses, anthers included in throat to slightly exserted; pollen blue or white, generally matching corolla lobe coloration, apertures pantoporate, acolpate; sexine seimitectate, reticulate, heterobrochate. Ovary three-chambered, stigmatic lobes three, included in to slightly exserted from corolla throat; capsule ~ 2.4-3.4 mm long, dehiscing circumcisally around the base with valves splitting upward. Seeds generally 4-8 per locule, medium brown, ovoid-angular, mucilaginous when wet. Nuclear gene loci showing diploid PCR amplification patterns.

Habitat, distribution, and phenology

Navarretia aeroides prefers (reddish) clay soils in forest openings from 400-1350(-1900) meters elevation. Occurrences are widely scattered in the Sierra Nevada from Mariposa County, California in the south to Plumas County in the North, and in the Trinity mountains of the North Coast Range, California. This species flowers primarily June-July.

Conservation status.

Many historical collections of this species are sufficiently general in their locality descriptions in areas now populated that our efforts to relocate them, compounded by recent drought years, have been unsuccessful. On the other hand, all but two of our collections were made serendipitously, in the course of looking for other species, suggesting our present knowledge of occurrences is incomplete. Following IUCN (2012) Red List version 3.1 criteria, this species is most accurately characterized as data deficient, though it may be Vulnerable based on the fragmented nature of a limited number of occurrences.

Etymology.

From the Latin Navarretia aeroides , like the sky or sky-blue, in reference to the typical color of the corolla.

Representative specimens examined

(paratypes). UNITED STATES OF AMERICA. California: El Dorado County, Lake Valley, July 1908, Brandegee s.n. (UC; mixed collection with N. divaricata ); 3 miles east of Camino at C.C.C. Camp Snowline, 3400 ft, 6 July 1943, Robbins 1247 (JEPS, UC); 0.1 mi north of Rescue , along deer valley road, 1300 ft, 30 June 1945, Robbins 2015 (UC); 3 miles southeast of Greenwood , Coloma Canyon, 18 June 1957, Crampton 4233 (AHUC); 6.4 miles east of Diamond Springs , 6 June 1960, Crampton 5546 (AHUC); Sly Park Vicinity. Park Creek Road off of county road E16, 38.7493°N, 120.4970°W, 1207 m, 8 July 2014, Johnson 14-142 (BRY, JEPS); Mariposa County , Telegraph Hill Road, ca. 7 miles from Hwy 140 via E. Whitelock Road, 37.5773°N, 120.0038°W, 809 m, 9 June 2015, Johnson 15-005 (BRY, JEPS); Nevada County, Colfax, 3 July 1882, Jones 3417. (POM, scan); Colfax, 20-22 Jun 1912, Eastwood 498 (CAS, UC); Rattlesnake Creek , 5 miles south of Grass Valley , 2000 ft, 29 May 1926, Mason 3279 (UC); Bed of dried pond west of Greenhorn Creek , T 16N R9E S24, 3000 ft, 27 August 1954, Raven 7980 (CAS); Placer County , Nevada City, Hospital Farm, Sierra Nevada Mtns, 5000 ft, 31 July 1915, Brainerd & Baird 236 (JEPS); 10 miles west of Forest Hill , 15 June 1955, Crampton 2921 (AHUC); Plumas County , 2.5 miles northeast of Quincy Junction on Mt Hough-Crystal Lake Road, T 24N R10E S4, 4200 ft, 24 June 1981, Barbe, Fuller, & Howell 3181 (CHSC); East of Quincy , about 2.3 miles along Mt. H road from its junction with Quincy Jct Road, at intersection with 25N14, 39.9747°N, 120.8761°W, 1321 m, 12 June 2015, Johnson 15-065 (BRY, JEPS) and 14 July 2016, Johnson 16-087 (BRY, JEPS); Trinity County , Hills south above Hayfork, between Kingsbury Rd. and Bridge Gulch Rd, 25 June 2005, Gowen 462; East side of Hwy 3 south of Clair Engle Lake , ca 2.3 miles south of Tannery Gulch Road , 40.8225°N, 122.8887°W, 947 m, 16 July 2009, Johnson 09-109 (BRY); About 7.3 miles up Wildwood Rd (NF-3) from Hwy 36, 40.4514°N, 123.0649°W, 1003 m, 13 July 2016, Johnson 16-063a (BRY); South of Hayfork about 3.3 miles along Kingsbury road from jct with Morgan Hill road, 40.5074°N, 123.1469°W, 851 m, 13 July 2016, Johnson 16-070 (BRY, JEPS); Yuba County , along margin of New York Flat Road, 0.5 miles north from jct with Laporte road (possible waif), 39.4812°N, 121.2606°W, 2255 ft, 18 June 2004, Johnson 04-150 (BRY) .

Notes.

Navarretia aeroides are mephic when fresh. In 2015, the population first collected by Barbe, Fuller, & Howell in the mountains east of Quincy, California, was found to have been sprayed with 2,4-D (and blue indicator dye), along with N. propinqua , in an area designated for ORV use, perhaps having been mistaken for immature thistle. To date, occurrences in the Trinity Mountains can be distinguished morphologically (white corollas with magenta streaking in the throat and white pollen) from occurrences in the Sierra Nevada (blue to light blue corollas and blue pollen), yet we have resisted recognizing this difference at the subspecific level. As in any species with colored corollas, occasional white flowered individuals are observed in the Sierra Nevada among a sea of blue flowered individuals. The paratype of Gilia atrata M.E.Jones from Colfax, California [POM-75128 scan!] belongs here.

Navarretia aeroides is a smaller-featured plant than either N. vividior or N. modocensis , though its corolla overlaps in size with N. vividior . The more conspicuously glandular inflorescence heads (in side-by-side comparisons) contrasts with all of the other species detailed here, and corolla coloration, fresh and dried, readily distinguishes this taxon from N. divaricata and N. torreyella .

Figures

Figure 4. Distribution of Navarretia vividior (circles), N. modocensis (squares), N. aeroides (triangles), and N. torreyella (4 - pointed stars) occurrences across their native range in California and southern Oregon, United States. Instances of observed syntopy are indicated with the hexagon and pentagon, as defined in the legend.

Figure 6. Navarretia aeroides. A Pressed specimen showing plant habit, scale bar = 1 cm (Gowen 1303) B Flowering head in the field, scale bar = 2 mm (Johnson 14 - 142) C-F Equivalent magnification, scale bar = 2 mm C, D Pressed flowering head showing range of coloration in dried flowers (Johnson 16 - 070, Gowen 1303, respectively) E, F Fresh flowers showing range of coloration (Johnson 16 - 063 a, Johnson 15 - 065, respectively). All photographs by L. A. Johnson and vouchers deposited at BRY.