Helianthus winteri is described from Fresno and Tulare Counties in the southern Sierra Nevada foothills of California. It is distinguished from H. annuus by its woody trunk, year-round blooming, and morphological characteristics. It occurs in open, ungrazed foothill woodlands and annual grasslands on well-drained, granitic soils, generally on lower-elevation, south-facing foothill slopes east of the San Joaquin Valley

Constable, John V. H.

Stebbins, John C

Winchell, Chris J

Keck Graduate Institute

Aliso: A Journal of Systematic and Evolutionary Botany
Volume 31 | Issue 1 Article 4
2013
Helianthus winteri (Asteraceae), a New Perennial
Species From the Southern Sierra Nevada
Foothills, California
John C. Stebbins
Chris J. Winchell
H.T. Harvey and Associates, Fresno, California
John V. H. Constable
Department of Biology, California State University, Fresno
Follow this and additional works at: http://scholarship.claremont.edu/aliso
Recommended Citation
Stebbins, John C.; Winchell, Chris J.; and Constable, John V. H. (2013) "Helianthus winteri (Asteraceae), a New Perennial Species
From the Southern Sierra Nevada Foothills, California," Aliso: A Journal of Systematic and Evolutionary Botany: Vol. 31: Iss. 1, Article 4.
Available at: http://scholarship.claremont.edu/aliso/vol31/iss1/4
HELIANTHUS WINTERI (ASTERACEAE), A NEW PERENNIAL SPECIES FROM THE SOUTHERN SIERRA
NEVADA FOOTHILLS, CALIFORNIA
JOHN C. STEBBINS,1 CHRIS J. WINCHELL,2 AND JOHN V. H. CONSTABLE3,4
1357 Adler Avenue, Clovis, California 93612;
2H.T. Harvey and Associates, Suite 310, 7815 N. Palm Avenue, Fresno, California 93711;
3Department of Biology, California State University, Fresno, California 93740
4Corresponding author (jconstable@csufresno.edu)
ABSTRACT
Helianthus winteri is described from Fresno and Tulare Counties in the southern Sierra Nevada foothills
of California. It is distinguished from H. annuus by its woody trunk, year-round blooming, and
morphological characteristics. It occurs in open, ungrazed foothill woodlands and annual grasslands on
well-drained, granitic soils, generally on lower-elevation, south-facing foothill slopes east of the San
Joaquin Valley.
Key words: Asteraceae, California, Helianthus winteri, Helianthus annuus, new species, North America,
Sierra Nevada foothills, sunflower.
TAXONOMIC TREATMENT
Helianthus winteri J.C.Stebbins, sp. nov. ‘‘Winter’s sunflower’’
(Fig. 1–10).—TYPE: USA. California, Fresno County: on
steep south-facing slopes in annual grassland, north side of
Highway 180, 0.6 km east of Cove Road, 36.7211701N,
119.3118021W, 335 m elevation, 01 Aug 2008, J. C. Stebbins
& C. J. Winchell 0423 (holotype RSA; isotypes CAS, FSC,
JEPS, UC).
Helianthus winteri occurrit praecipue in clivis spectantibus ad
meridianam coeli partem in collibus australibus Sierrae Nevadae et a
specie communi pervagataque H. annuo in forma distinguitur statura
grandi (usque 4 m altitudine); caulibus persistentibus perennibus
lignosisque; et florescentia per totum annum. Differentiae additiciae
includunt achenia valde minora; colorem purpurascentem saturatum
caulium juvenium, palearum phyllariorumque; et praesentiam exsuda-
torum resinosorum in caulibus lignosis.
Subshrub to 4 m tall. Trunk generally solitary, erect or
ascending, to 8 cm in diameter at base, proximally un-
branched, bark gray-brown; branches ascending; young stems
purplish-maroon, hirsute, hairs stout, spreading, pustulate-
based, 2–4 mm, and strigose hairs finer, 0.2–1 mm, and
minutely glandular-puberulent, hairs6 0.1 mm. Leaves mostly
alternate; petioles of principal leaves 6–12 cm, blades 3-veined,
12–14 cm, widely ovate, base widely cuneate to truncate or
cordate, apex acute to acuminate, margins serrate; distal
leaves: petioles shorter, blades lance-ovate to lanceolate,
smaller; abaxial surfaces of blades hispid along veins, hairs
0.5–2 mm, densely hirtellous between veins, hairs finer, 6
0.2 mm, and dotted with minute sessile resin glands, adaxial
surfaces hispid and hirtellous, hairs 0.1–1 mm, and dotted with
minute resin glands. Heads radiate, in openly branched,
paniculiform capitulescences; peduncles ascending 4–24 cm;
involucres cupuliform, 3–4 cm diameter; phyllaries ovate to
acuminate, 12–20 mm, abaxially hispid, hirtellous, glandular-
puberulent, purplish and resin-dotted, adaxially glandular-
puberulent, margins ciliate, hairs stiff, straight or curved, 0.5–
1.5 mm; paleae 9–10 mm, 3-lobed, middle lobe long-
acuminate, darkly pigmented, hirtellous. Ray florets 12–34;
laminae bright yellow, 6 20 mm long, 5–8 mm wide. Disc
florets many; corollas yellow, 6–6.5 mm, tube 1 mm, throat
3.5–4 mm, proximally swollen, distally cylindric, lobes ovate 6
1.5 mm, acute, tube and proximal bulge of throat puberulent,
hairs stiff, ascending, acuminate, distal throat and lobes
glabrous; anthers 6 4 mm, reddish brown; shaft of style
4.5 mm, branches 2.5 mm, glabrous in proximal 1 mm, distally
densely hirtellous, reddish brown. Achenes 6 3.5 mm, weakly
compressed, gray-brown, densely covered with ascending hairs
0.2–1.0 mm; pappus scales lanceolate, 2.5–3 mm, 2n 5 34.
Stem morphology varies with plant age and environmental
and edaphic conditions. Young herbaceous stems of first-year
plants appear indistinguishable from those of H. annuus L.;
stems of older plants are woody and have abundant resinous
secretions.
Distribution and habitat.—The nine known H. winteri sites
(Fig. 11) are found in relatively steep, open areas (ungrazed,
south-facing, grassy slopes, rock outcrops, roadcuts; Fig. 12–
13) on well-drained granitic soils in the northern portion of
southern Sierra Nevada foothills at elevations of 180–460 m.
Associated species include Avena barbata Link, A. fatua L.,
Carduus pycnocephalus L., Quercus douglasii Hook. & Arn., Q.
wislizeni A. DC., Frangula californica (Eschsch.) A.Gray,
Bromus diandrus Roth., B. hordeaceus L., B. madritensis L.
subsp. rubens (L.) Husn., B. tectorum L., Caulanthus coulteri
S.Watson, Phacelia cicutaria Greene, Chaenactis glabriuscula
DC. var. glabriuscula, Eschscholzia caespitosa Benth., Poa
bulbosa L., P. secunda J.Presl., Plagiobothrys nothofulvus
(A.Gray) A.Gray, P. tenellus (Hook.) A.Gray, Erodium botrys
(Cav.) Bertol., E. cicutarium (L.) Aiton, Amsinckia eastwoodiae
J.F.Macbr., A. intermedia Fisch. & C.A.Mey., Pholistoma
auritum (Lindl.) Lilja var. auritum, Lupinus albifrons Benth.
var. albifrons, L. bicolor Lindl., L. benthamii A.Heller,
Scrophularia californica Cham. & Schltdl., Thysanocarpus
curvipes Hook., Dichelostemma capitatum (Benth.) Alph.
Wood subsp. capitatum, and Datura wrightii Regel.
Paratypes (CAS, FSC, JEPS, RSA, UC).—USA. California,
Fresno County: 36.7201911N, 119.3143022W, 345 m eleva-
Aliso, 31(1), pp. 19–24
’ 2013, The Author(s), CC-BY
tion, 1 Aug 2008, J. C. Stebbins & C. J. Winchell 0426;
36.7201011N, 119.3169033W, 330 m elevation, 4 Dec 2010, J.
C. Stebbins & C. J. Winchell 3348; 36.7201920N,
119.3137220W, 335 m elevation, 4 Dec 2010, J. C. Stebbins
& C. J. Winchell 3349; 2.3 km N of American Avenue, E of
Friant-Kern Canal and W of Avenue 32, 36.671516N,
119.330467W, 330 m elevation, 12 Oct 2012, J. C. Stebbins &
J. V. H. Constable 12940; 2.6 km N of American Avenue and
0.2 km NW of Avenue 32 adjacent to Southern California
Edison Company transmission lines, 36.681000N,
119.332900W, 335 m elevation, 12 Oct 2012, J. C. Stebbins &
J. V. H. Constable 12941. Tulare County: N side of Avenue
448, 0.2 km S of Highway 63, 36.603300N, 119.292383W,
320 m elevation, 12 Oct 2012, J. C. Stebbins & J. V. H.
Constable 12942; E side of Friant-Kern Canal and SW of
Curtis Mountain adjacent to Southern California Edison
Company transmission lines, 36.593016N, 119.284050W,
325 m elevation, 12 Oct 2012, J. C. Stebbins & J. V. H.
Constable 12943; N side of Boyd Drive, 2.3 km NE of Avenue
416 on south-facing slope, 36.559150N, 119.192433W, 340 m
elevation, 12 Oct 2012, J. C. Stebbins & J. V. H. Constable
12944; 0.5 km NE of Friant-Kern Canal on S slope of Curtis
Mountain, 36.589617N, 119.257733W, 335 m elevation, 7 Jan
2013, J. C. Stebbins & J. V. H. Constable 12945.
Etymology.—Helianthus winteri is named in honor of Robert
F. (Bob) Winter, emeritus Fresno City College instructor who
has influenced the development of many California biologists,
Fig. 1–4. Helianthus winteri J.C.Stebbins (Winter’s sunflower).—1. Shoot structure.—2. Leaf.—3. Inflorescence with detail of phyllaries.—4.
Inflorescence from above. Line drawings by Shannon Bickford.
20 Stebbins, Winchell, Constable ALISO
and natural historians within and beyond the range of this newly
described species. His comment to ‘‘look at that big sunflower
(blooming in January) up there’’ eventually prompted this closer
analysis of a plant that superficially appeared to be H. annuus.
The fact that the plants routinely flower year-round, including the
winter months, lends further justification to the specific epithet.
NOTES AND DISCUSSION
Helianthus winteri is known from a relatively limited
geographic and elevation range in southern Fresno County
and northern Tulare County (Fig. 11). The type locality for the
species is directly adjacent to Highway 180 east of Fresno,
which represents a major access route to Sequoia and Kings
Canyon National Parks. Many plants of this species grown in
cultivation readily succumbed to frost, suggesting frost as a
major determinant in the distribution of the species. Plants
with woody stems tolerate severe frosts and the occasional low
elevation snowfall at some sites. Localization of the plants on
steep, rocky, south-facing slopes may benefit survival due to
increased temperatures (enhanced insolation of southern
exposures), enhanced water availability (rocky terrain creates
surface runoff), and protection from domestic livestock
grazing in these microhabitats. Presence of H. winteri only
on slopes with little apparent livestock grazing suggests
intolerance of herbivory similar to that of some other
California native species (e.g., species of Clarkia Pursh,
Aristida L., Stipa L.) that remain physiologically active during
the late spring and summer (Ornduff 1974). Young plants of
H. annuus are not tolerant of intensive grazing and occur
primarily on roadsides and fallow and ruderal ‘‘waste’’ areas
where domestic grazing does not occur (Abrams and Ferris
1960; Munz 1973). Helianthus annuus also occurs at some of
the H. winteri sites, where it flowers only between April and
October. Accessible foothill habitat within the known range of
H. winteri that is not developed or farmed is subject to grazing
on a year-round basis, although livestock is sometimes
excluded from steep rocky slopes due to safety concerns or
the low forage value of these locations. Identification of sites
that may support H. winteri is aided by observations of fence
lines that may indicate sites with lower grazing intensity. The
details of the causal relationship between the distribution ofH.
winteri and site characteristics (e.g., slope, aspect, grazing
intensity and timing, and presence of invasive plant species)
require further examination. It is likely that H. winteri
historically occurred at lower elevations and on less rocky
sites on the east side of the southern San Joaquin Valley.
However, these lands are now intensively managed for
agriculture or support highly developed infrastructure, and
the species is now likely eliminated from these sites. Helianthus
winteri may occur in similar habitats northwards in the central
Sierra Nevada Foothills and southwards in the southern Sierra
Nevada Foothills. Based upon ecological and geographic
restrictions, H. winteri should be evaluated as a potential rare
plant by the California Native Plant Society and the state and
federal agencies with jurisdiction over rare species.
Phenological and morphological features that distinguish H.
winteri from H. annuus are its year-round flowering and woody
stem (Fig. 12–15). Individuals of H. winteri flower throughout
the year, even after significant freezes. Stems that persist for
years become woody (Fig. 14), and damaged stems display
regrowth patterns similar to those of other woody plants.
Stems increase in diameter through what appear to be more or
less distinct growth rings (Fig. 15; S. Leavitt, pers. comm., 11
Apr 2013). Evolution of woody taxa from herbaceous
progenitors is well established (e.g., Bo¨hle et al. 1996; Ballard
and Sytsma 2000), and such a transformation may occur
relatively rapidly with minimal genetic change (Thomas et al.
Fig. 5–10. Floral structure of Helianthus winteri J.C.Stebbins (Winter’s sunflower).—5. Palea dorsal view.—6. Palea ventral view.—7. Disc
floret.—8. Disc floret with part of corolla removed.—9. Disc floret style.—10. Achene with pappus. Line drawings by Shannon Bickford.
VOLUME 31, NUMBER 1 A New Helianthus Species 21
2000; Groover 2005), such that the genetic distinction
between H. winteri and H. annuus may be subtle. Molecular
studies suggest that the development of woody characteristics
may be linked to the timing of flowering (Melzer et al. 2008;
Lens et al. 2012). Field observations of first-year plants of H.
winteri and H. annuus reveal relatively few clear morpholog-
ical differences; however, differences in vascular differentia-
tion has been observed as early as three weeks post-
germination (Moyers and Rieseberg 2013). Ongoing studies
of the genetic differences between H. winteri and H. annuus
indicate equivalent genome size between the two species, and
identical ploidy levels (2n 5 34). Nonetheless, genetic
differentiation between the two species has been observed
(B. Moyers, pers. comm., 6 May 2013). Examination of
phylogenetic relationships between H. winteri and other
Helianthus species (e.g., H. annuus, H. bolanderi A.Gray, H.
exilis A.Gray, and others) demonstrates that H. winteri
consistently clusters more closely with H. annuus than with
other annual Helianthus species (B. Moyers, pers. comm., 6
May 2013). Helianthus inexpectatus D.J.Keil & Elvin was
recently recognized as a rare sunflower from Southern
California based on a combination of geographic isolation
and ploidy level, but it displays inconsistent morphological
differences (Keil and Elvin 2010; Keil 2012). As described
here, H. winteri is recognized as a separate species by the
combination of morphological and phenological attributes
coupled with its presence in sites with specific ecological and
geographical features.
A PARTIAL KEY TO PERENNIAL CALIFORNIA
HELIANTHUS SPECIES SIMILAR TO H. WINTERI
1. Plant from taproot, subshrub, mature stems woody;
immature stems with bark at base; buds and phyllaries
generally purplish; blooms year-round; southern Sierra
Nevada Foothills (Fresno and Tulare Counties) . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . H. winteri
19 Plant from rhizome, stems not woody at base, buds not
purplish
2. Phyllaries generally 3–5 mm wide, tips of outer generally
reflexed at maturity . . . . . . . . . . . . . . . . H. californicus
29 Phyllaries generally , 3 mm wide, tips 6 erect to
reflexed at maturity
3. Phyllaries generally 2–3 mm wide, tips generally
spreading to reflexed . . . . . . . . . . H. inexpectatus
39 Phyllaries generally 1–1.5 mm wide, tips of outer
6 spreading to erect . . . . . . . . . . . H. nuttallii
ACKNOWLEDGMENTS
Preparation of this manuscript was aided by many
individuals with whom ideas and the potential significance of
Helianthus winteri were discussed. Particularly significant were
Fig. 11. Distribution of known populations of Helianthus winteri J.C.Stebbins (Winter’s sunflower).
22 Stebbins, Winchell, Constable ALISO
Brook Moyers and others in Dr. L. Reiseberg’s laboratory at the
University of BritishColumbia; andDr. Bruce Baldwin at the Jepson
Herbarium at the University of California, Berkeley. We thank Ms.
Shannon Bickford, whose patience in producing the drawings is
appreciated;Dr. H. Chapman at California StateUniversity, Fresno,
who translated the species description into Latin; and Dr. A.
Caldero´n-Urrea and Dr. P. Van de Water at California State
University, Fresno, who provided expertise in microscopy. We are
grateful to Dr. X. Yang at the California State University, Fresno,
Geospatial Information Center for the range map and to Dr. S.
Leavitt at the University of Arizona, Laboratory of Tree-Ring
Research for his expertise in wood structure. We appreciate the
careful reviews of themanuscript byDr. J. Strother andMs. J.Clines.
LITERATURE CITED
ABRAMS, L. AND R. S. FERRIS. 1960. Illustrated flora of the Pacific
states. Vol. IV: bignonias to sunflowers with index to vols. I–IV.
Stanford University Press, Stanford, California. 732 p.
BALLARD, H. E. AND K. J. SYTSMA. 2000. Evolution and biogeog-
raphy of woody Hawaiian violets (Viola, Violaceae): arctic
origins, herbaceous ancestry and bird dispersal. Evolution 54:
1521–1532.
BO¨HLE, U. R., H. H. HILGER, AND W. F. MARTIN. 1996. Island
colonization and evolution of the insular woody habit in Echium L.
(Boraginaceae). Proc. Natl. Acad. Sci. U.S.A. 93: 11740–
11745.
GROOVER, A. T. 2005. What genes make a tree a tree? Trends Pl. Sci.
10: 210–214.
KEIL, D. J. 2012. Helianthus, pp. 343–344. In Baldwin, B. G., D. H.
Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken
[eds.], The Jepson manual: vascular plants of California, 2nd ed.
University of California Press, Berkeley.
AND M. A. ELVIN. 2010. Helianthus inexpectatus (Asteraceae),
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LENS, F., E. SMETS, AND S. MELZER. 2012. Stem anatomy supports
Arabidopsis thaliana as a model for insular woodiness. New Phytol.
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Fig. 12–15. Helianthus winteri J.C.Stebbins (Winter’s sunflower).—12. Growth habit, March 2008 at type locality.—13. The same individual
as in Fig. 12, October 2010.—14. Stem illustrating woody characteristics and resinous secretions (arrows), scale bar 5 cm.—15. Stem transverse
section at 103 magnification, scale bar 200 mm.
VOLUME 31, NUMBER 1 A New Helianthus Species 23
MELZER, S., F. LENS, J. GENNEN, S. VANNESTE, A. ROHDE, AND T.
BEECKMAN. 2008. Flowering-time genes modulate meristem deter-
minacy and growth form in Arabidopsis thaliana. Nat. Genet. 40:
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MOYERS, B. T. AND L. H. RIESEBERG. 2013. Divergence in gene
expression is uncoupled from divergence in coding sequence in a
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MUNZ, P. A. 1973. A California flora and supplement (in collaboration
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24 Stebbins, Winchell, Constable ALISO


English

Helianthus winteri (Asteraceae), a New Perennial Species From the Southern Sierra Nevada Foothills, California

Scholarship@Claremont

Aliso: A Journal of Systematic and Evolutionary BotanyVolume 31 | Issue 1 Article 42013Helianthus winteri (Asteraceae), a New PerennialSpecies From the Southern Sierra NevadaFoothills, CaliforniaJohn C. StebbinsChris J. WinchellH.T. Harvey and Associates, Fresno, CaliforniaJohn V. H. ConstableDepartment of Biology, California State University, FresnoFollow this and additional works at: http://scholarship.claremont.edu/alisoRecommended CitationStebbins, John C.; Winchell, Chris J.; and Constable, John V. H. (2013) "Helianthus winteri (Asteraceae), a New Perennial SpeciesFrom the Southern Sierra Nevada Foothills, California," Aliso: A Journal of Systematic and Evolutionary Botany: Vol. 31: Iss. 1, Article 4.Available at: http://scholarship.claremont.edu/aliso/vol31/iss1/4HELIANTHUS WINTERI (ASTERACEAE), A NEW PERENNIAL SPECIES FROM THE SOUTHERN SIERRANEVADA FOOTHILLS, CALIFORNIAJOHN C. STEBBINS,1 CHRIS J. WINCHELL,2 AND JOHN V. H. CONSTABLE3,41357 Adler Avenue, Clovis, California 93612;2H.T. Harvey and Associates, Suite 310, 7815 N. Palm Avenue, Fresno, California 93711;3Department of Biology, California State University, Fresno, California 937404Corresponding author (jconstable@csufresno.edu)ABSTRACTHelianthus winteri is described from Fresno and Tulare Counties in the southern Sierra Nevada foothillsof California. It is distinguished from H. annuus by its woody trunk, year-round blooming, andmorphological characteristics. It occurs in open, ungrazed foothill woodlands and annual grasslands onwell-drained, granitic soils, generally on lower-elevation, south-facing foothill slopes east of the SanJoaquin Valley.Key words: Asteraceae, California, Helianthus winteri, Helianthus annuus, new species, North America,Sierra Nevada foothills, sunflower.TAXONOMIC TREATMENTHelianthus winteri J.C.Stebbins, sp. nov. ‘‘Winter’s sunflower’’(Fig. 1–10).—TYPE: USA. California, Fresno County: onsteep south-facing slopes in annual grassland, north side ofHighway 180, 0.6 km east of Cove Road, 36.7211701N,119.3118021W, 335 m elevation, 01 Aug 2008, J. C. Stebbins& C. J. Winchell 0423 (holotype RSA; isotypes CAS, FSC,JEPS, UC).Helianthus winteri occurrit praecipue in clivis spectantibus admeridianam coeli partem in collibus australibus Sierrae Nevadae et aspecie communi pervagataque H. annuo in forma distinguitur staturagrandi (usque 4 m altitudine); caulibus persistentibus perennibuslignosisque; et florescentia per totum annum. Differentiae additiciaeincludunt achenia valde minora; colorem purpurascentem saturatumcaulium juvenium, palearum phyllariorumque; et praesentiam exsuda-torum resinosorum in caulibus lignosis.Subshrub to 4 m tall. Trunk generally solitary, erect orascending, to 8 cm in diameter at base, proximally un-branched, bark gray-brown; branches ascending; young stemspurplish-maroon, hirsute, hairs stout, spreading, pustulate-based, 2–4 mm, and strigose hairs finer, 0.2–1 mm, andminutely glandular-puberulent, hairs6 0.1 mm. Leaves mostlyalternate; petioles of principal leaves 6–12 cm, blades 3-veined,12–14 cm, widely ovate, base widely cuneate to truncate orcordate, apex acute to acuminate, margins serrate; distalleaves: petioles shorter, blades lance-ovate to lanceolate,smaller; abaxial surfaces of blades hispid along veins, hairs0.5–2 mm, densely hirtellous between veins, hairs finer, 60.2 mm, and dotted with minute sessile resin glands, adaxialsurfaces hispid and hirtellous, hairs 0.1–1 mm, and dotted withminute resin glands. Heads radiate, in openly branched,paniculiform capitulescences; peduncles ascending 4–24 cm;involucres cupuliform, 3–4 cm diameter; phyllaries ovate toacuminate, 12–20 mm, abaxially hispid, hirtellous, glandular-puberulent, purplish and resin-dotted, adaxially glandular-puberulent, margins ciliate, hairs stiff, straight or curved, 0.5–1.5 mm; paleae 9–10 mm, 3-lobed, middle lobe long-acuminate, darkly pigmented, hirtellous. Ray florets 12–34;laminae bright yellow, 6 20 mm long, 5–8 mm wide. Discflorets many; corollas yellow, 6–6.5 mm, tube 1 mm, throat3.5–4 mm, proximally swollen, distally cylindric, lobes ovate 61.5 mm, acute, tube and proximal bulge of throat puberulent,hairs stiff, ascending, acuminate, distal throat and lobesglabrous; anthers 6 4 mm, reddish brown; shaft of style4.5 mm, branches 2.5 mm, glabrous in proximal 1 mm, distallydensely hirtellous, reddish brown. Achenes 6 3.5 mm, weaklycompressed, gray-brown, densely covered with ascending hairs0.2–1.0 mm; pappus scales lanceolate, 2.5–3 mm, 2n 5 34.Stem morphology varies with plant age and environmentaland edaphic conditions. Young herbaceous stems of first-yearplants appear indistinguishable from those of H. annuus L.;stems of older plants are woody and have abundant resinoussecretions.Distribution and habitat.—The nine known H. winteri sites(Fig. 11) are found in relatively steep, open areas (ungrazed,south-facing, grassy slopes, rock outcrops, roadcuts; Fig. 12–13) on well-drained granitic soils in the northern portion ofsouthern Sierra Nevada foothills at elevations of 180–460 m.Associated species include Avena barbata Link, A. fatua L.,Carduus pycnocephalus L., Quercus douglasii Hook. & Arn., Q.wislizeni A. DC., Frangula californica (Eschsch.) A.Gray,Bromus diandrus Roth., B. hordeaceus L., B. madritensis L.subsp. rubens (L.) Husn., B. tectorum L., Caulanthus coulteriS.Watson, Phacelia cicutaria Greene, Chaenactis glabriusculaDC. var. glabriuscula, Eschscholzia caespitosa Benth., Poabulbosa L., P. secunda J.Presl., Plagiobothrys nothofulvus(A.Gray) A.Gray, P. tenellus (Hook.) A.Gray, Erodium botrys(Cav.) Bertol., E. cicutarium (L.) Aiton, Amsinckia eastwoodiaeJ.F.Macbr., A. intermedia Fisch. & C.A.Mey., Pholistomaauritum (Lindl.) Lilja var. auritum, Lupinus albifrons Benth.var. albifrons, L. bicolor Lindl., L. benthamii A.Heller,Scrophularia californica Cham. & Schltdl., Thysanocarpuscurvipes Hook., Dichelostemma capitatum (Benth.) Alph.Wood subsp. capitatum, and Datura wrightii Regel.Paratypes (CAS, FSC, JEPS, RSA, UC).—USA. California,Fresno County: 36.7201911N, 119.3143022W, 345 m eleva-Aliso, 31(1), pp. 19–24’ 2013, The Author(s), CC-BYtion, 1 Aug 2008, J. C. Stebbins & C. J. Winchell 0426;36.7201011N, 119.3169033W, 330 m elevation, 4 Dec 2010, J.C. Stebbins & C. J. Winchell 3348; 36.7201920N,119.3137220W, 335 m elevation, 4 Dec 2010, J. C. Stebbins& C. J. Winchell 3349; 2.3 km N of American Avenue, E ofFriant-Kern Canal and W of Avenue 32, 36.671516N,119.330467W, 330 m elevation, 12 Oct 2012, J. C. Stebbins &J. V. H. Constable 12940; 2.6 km N of American Avenue and0.2 km NW of Avenue 32 adjacent to Southern CaliforniaEdison Company transmission lines, 36.681000N,119.332900W, 335 m elevation, 12 Oct 2012, J. C. Stebbins &J. V. H. Constable 12941. Tulare County: N side of Avenue448, 0.2 km S of Highway 63, 36.603300N, 119.292383W,320 m elevation, 12 Oct 2012, J. C. Stebbins & J. V. H.Constable 12942; E side of Friant-Kern Canal and SW ofCurtis Mountain adjacent to Southern California EdisonCompany transmission lines, 36.593016N, 119.284050W,325 m elevation, 12 Oct 2012, J. C. Stebbins & J. V. H.Constable 12943; N side of Boyd Drive, 2.3 km NE of Avenue416 on south-facing slope, 36.559150N, 119.192433W, 340 melevation, 12 Oct 2012, J. C. Stebbins & J. V. H. Constable12944; 0.5 km NE of Friant-Kern Canal on S slope of CurtisMountain, 36.589617N, 119.257733W, 335 m elevation, 7 Jan2013, J. C. Stebbins & J. V. H. Constable 12945.Etymology.—Helianthus winteri is named in honor of RobertF. (Bob) Winter, emeritus Fresno City College instructor whohas influenced the development of many California biologists,Fig. 1–4. Helianthus winteri J.C.Stebbins (Winter’s sunflower).—1. Shoot structure.—2. Leaf.—3. Inflorescence with detail of phyllaries.—4.Inflorescence from above. Line drawings by Shannon Bickford.20 Stebbins, Winchell, Constable ALISOand natural historians within and beyond the range of this newlydescribed species. His comment to ‘‘look at that big sunflower(blooming in January) up there’’ eventually prompted this closeranalysis of a plant that superficially appeared to be H. annuus.The fact that the plants routinely flower year-round, including thewinter months, lends further justification to the specific epithet.NOTES AND DISCUSSIONHelianthus winteri is known from a relatively limitedgeographic and elevation range in southern Fresno Countyand northern Tulare County (Fig. 11). The type locality for thespecies is directly adjacent to Highway 180 east of Fresno,which represents a major access route to Sequoia and KingsCanyon National Parks. Many plants of this species grown incultivation readily succumbed to frost, suggesting frost as amajor determinant in the distribution of the species. Plantswith woody stems tolerate severe frosts and the occasional lowelevation snowfall at some sites. Localization of the plants onsteep, rocky, south-facing slopes may benefit survival due toincreased temperatures (enhanced insolation of southernexposures), enhanced water availability (rocky terrain createssurface runoff), and protection from domestic livestockgrazing in these microhabitats. Presence of H. winteri onlyon slopes with little apparent livestock grazing suggestsintolerance of herbivory similar to that of some otherCalifornia native species (e.g., species of Clarkia Pursh,Aristida L., Stipa L.) that remain physiologically active duringthe late spring and summer (Ornduff 1974). Young plants ofH. annuus are not tolerant of intensive grazing and occurprimarily on roadsides and fallow and ruderal ‘‘waste’’ areaswhere domestic grazing does not occur (Abrams and Ferris1960; Munz 1973). Helianthus annuus also occurs at some ofthe H. winteri sites, where it flowers only between April andOctober. Accessible foothill habitat within the known range ofH. winteri that is not developed or farmed is subject to grazingon a year-round basis, although livestock is sometimesexcluded from steep rocky slopes due to safety concerns orthe low forage value of these locations. Identification of sitesthat may support H. winteri is aided by observations of fencelines that may indicate sites with lower grazing intensity. Thedetails of the causal relationship between the distribution ofH.winteri and site characteristics (e.g., slope, aspect, grazingintensity and timing, and presence of invasive plant species)require further examination. It is likely that H. winterihistorically occurred at lower elevations and on less rockysites on the east side of the southern San Joaquin Valley.However, these lands are now intensively managed foragriculture or support highly developed infrastructure, andthe species is now likely eliminated from these sites. Helianthuswinteri may occur in similar habitats northwards in the centralSierra Nevada Foothills and southwards in the southern SierraNevada Foothills. Based upon ecological and geographicrestrictions, H. winteri should be evaluated as a potential rareplant by the California Native Plant Society and the state andfederal agencies with jurisdiction over rare species.Phenological and morphological features that distinguish H.winteri from H. annuus are its year-round flowering and woodystem (Fig. 12–15). Individuals of H. winteri flower throughoutthe year, even after significant freezes. Stems that persist foryears become woody (Fig. 14), and damaged stems displayregrowth patterns similar to those of other woody plants.Stems increase in diameter through what appear to be more orless distinct growth rings (Fig. 15; S. Leavitt, pers. comm., 11Apr 2013). Evolution of woody taxa from herbaceousprogenitors is well established (e.g., Bo¨hle et al. 1996; Ballardand Sytsma 2000), and such a transformation may occurrelatively rapidly with minimal genetic change (Thomas et al.Fig. 5–10. Floral structure of Helianthus winteri J.C.Stebbins (Winter’s sunflower).—5. Palea dorsal view.—6. Palea ventral view.—7. Discfloret.—8. Disc floret with part of corolla removed.—9. Disc floret style.—10. Achene with pappus. Line drawings by Shannon Bickford.VOLUME 31, NUMBER 1 A New Helianthus Species 212000; Groover 2005), such that the genetic distinctionbetween H. winteri and H. annuus may be subtle. Molecularstudies suggest that the development of woody characteristicsmay be linked to the timing of flowering (Melzer et al. 2008;Lens et al. 2012). Field observations of first-year plants of H.winteri and H. annuus reveal relatively few clear morpholog-ical differences; however, differences in vascular differentia-tion has been observed as early as three weeks post-germination (Moyers and Rieseberg 2013). Ongoing studiesof the genetic differences between H. winteri and H. annuusindicate equivalent genome size between the two species, andidentical ploidy levels (2n 5 34). Nonetheless, geneticdifferentiation between the two species has been observed(B. Moyers, pers. comm., 6 May 2013). Examination ofphylogenetic relationships between H. winteri and otherHelianthus species (e.g., H. annuus, H. bolanderi A.Gray, H.exilis A.Gray, and others) demonstrates that H. wintericonsistently clusters more closely with H. annuus than withother annual Helianthus species (B. Moyers, pers. comm., 6May 2013). Helianthus inexpectatus D.J.Keil & Elvin wasrecently recognized as a rare sunflower from SouthernCalifornia based on a combination of geographic isolationand ploidy level, but it displays inconsistent morphologicaldifferences (Keil and Elvin 2010; Keil 2012). As describedhere, H. winteri is recognized as a separate species by thecombination of morphological and phenological attributescoupled with its presence in sites with specific ecological andgeographical features.A PARTIAL KEY TO PERENNIAL CALIFORNIAHELIANTHUS SPECIES SIMILAR TO H. WINTERI1. Plant from taproot, subshrub, mature stems woody;immature stems with bark at base; buds and phyllariesgenerally purplish; blooms year-round; southern SierraNevada Foothills (Fresno and Tulare Counties) . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . H. winteri19 Plant from rhizome, stems not woody at base, buds notpurplish2. Phyllaries generally 3–5 mm wide, tips of outer generallyreflexed at maturity . . . . . . . . . . . . . . . . H. californicus29 Phyllaries generally , 3 mm wide, tips 6 erect toreflexed at maturity3. Phyllaries generally 2–3 mm wide, tips generallyspreading to reflexed . . . . . . . . . . H. inexpectatus39 Phyllaries generally 1–1.5 mm wide, tips of outer6 spreading to erect . . . . . . . . . . . H. nuttalliiACKNOWLEDGMENTSPreparation of this manuscript was aided by manyindividuals with whom ideas and the potential significance ofHelianthus winteri were discussed. Particularly significant wereFig. 11. Distribution of known populations of Helianthus winteri J.C.Stebbins (Winter’s sunflower).22 Stebbins, Winchell, Constable ALISOBrook Moyers and others in Dr. L. Reiseberg’s laboratory at theUniversity of BritishColumbia; andDr. Bruce Baldwin at the JepsonHerbarium at the University of California, Berkeley. We thank Ms.Shannon Bickford, whose patience in producing the drawings isappreciated;Dr. H. Chapman at California StateUniversity, Fresno,who translated the species description into Latin; and Dr. A.Caldero´n-Urrea and Dr. P. Van de Water at California StateUniversity, Fresno, who provided expertise in microscopy. We aregrateful to Dr. X. Yang at the California State University, Fresno,Geospatial Information Center for the range map and to Dr. S.Leavitt at the University of Arizona, Laboratory of Tree-RingResearch for his expertise in wood structure. We appreciate thecareful reviews of themanuscript byDr. J. Strother andMs. J.Clines.LITERATURE CITEDABRAMS, L. AND R. S. FERRIS. 1960. Illustrated flora of the Pacificstates. Vol. IV: bignonias to sunflowers with index to vols. I–IV.Stanford University Press, Stanford, California. 732 p.BALLARD, H. E. AND K. J. SYTSMA. 2000. Evolution and biogeog-raphy of woody Hawaiian violets (Viola, Violaceae): arcticorigins, herbaceous ancestry and bird dispersal. Evolution 54:1521–1532.BO¨HLE, U. R., H. H. HILGER, AND W. F. MARTIN. 1996. Islandcolonization and evolution of the insular woody habit in Echium L.(Boraginaceae). Proc. Natl. Acad. Sci. U.S.A. 93: 11740–11745.GROOVER, A. T. 2005. What genes make a tree a tree? Trends Pl. Sci.10: 210–214.KEIL, D. J. 2012. Helianthus, pp. 343–344. In Baldwin, B. G., D. H.Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken[eds.], The Jepson manual: vascular plants of California, 2nd ed.University of California Press, Berkeley.AND M. A. ELVIN. 2010. Helianthus inexpectatus (Asteraceae),A tetraploid perennial new species from southern California. Aliso28: 59–62.LENS, F., E. SMETS, AND S. MELZER. 2012. Stem anatomy supportsArabidopsis thaliana as a model for insular woodiness. New Phytol.193: 12–17.Fig. 12–15. Helianthus winteri J.C.Stebbins (Winter’s sunflower).—12. Growth habit, March 2008 at type locality.—13. The same individualas in Fig. 12, October 2010.—14. Stem illustrating woody characteristics and resinous secretions (arrows), scale bar 5 cm.—15. Stem transversesection at 103 magnification, scale bar 200 mm.VOLUME 31, NUMBER 1 A New Helianthus Species 23MELZER, S., F. LENS, J. GENNEN, S. VANNESTE, A. ROHDE, AND T.BEECKMAN. 2008. Flowering-time genes modulate meristem deter-minacy and growth form in Arabidopsis thaliana. Nat. Genet. 40:1489–1492.MOYERS, B. T. AND L. H. RIESEBERG. 2013. Divergence in geneexpression is uncoupled from divergence in coding sequence in asecondarily woody sunflower. Int. J. Pl. Sci. 174: 1079–1089.MUNZ, P. A. 1973. A California flora and supplement (in collaborationwith D. D. Keck). University of California Press, Berkeley. 1681 p.,suppl. 224 p.ORNDUFF, R. 1974. An introduction to California plant life. Universityof California Press, Berkeley. 152 p.THOMAS, H., H. M. THOMAS, AND H. OUGHAM. 2000. Annuality,perenniality and cell death. J. Exp. Bot. 51: 1781–1788.24 Stebbins, Winchell, Constable ALISO

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Helianthus winteri (Asteraceae), a New Perennial Species From the Southern Sierra Nevada Foothills, California

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