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Abstract Detail

Systematics Section/ASPT

Winchell, Chris [1], Stebbins, John [2], Constable, John [3].

A new sunflower (Helianthus) species from Central California.

A new species, Winter's Sunflower (Helianthus winterii),is described from the Sierra Nevada foothills in central California. The new species is distinguished from the common sunflower (Helianthus annuus) by its perennial growth habit, woody trunk and year round bloom. The species description is based on growth habit and phenology, leaf form and morphology, structure of the phyllaries, ray and disk florets, and seed morphology. Helianthus winterii occurs in annual grassland and open foothill woodlands on steep well-drained granitic soils in limited locations in southern Fresno and northern Tulare Counties on relatively steep open areas on well-drained soils within foothill woodlands between 180 and 460 m. Subshrub <4 m tall, trunk generally solitary, erect or ascending, <8 cm diameter at base, proximally unbranched, bark gray-brown; branches many, ascending; young stem hirsute with stout spreading pustulate-based trichomes 2-4 mm, strigose with finer trichomes 0.2-1 mm, minutely glandular-puberulent with trichomes ±0.1 mm. Leaves mostly alternate; petioles of principal leaves 6-12 cm, blades 3-veined, 12-14 cm,widely ovate, widely cuneate to truncate or cordate at base, acute to acuminate at apex, serrate; distal leaves shorter petioled, lance-ovate to lanceolate,and reduced in size; abaxial surface of blades hispid along the veins with trichomes 0.5-2 mm, densely hirtellous between the veins with finer trichomes ±0.2 mm and dotted with minute sessile resin glands, adaxial surface hispid and hirtellous with mixture of trichomes0.1-1 mm and dotted with minute resin glands. Heads radiate, in openly branched paniculiform clusters with ascending branches; peduncles 2-24cm; involucres 3-4 cm diameter, cupuliform; phyllaries 12-20 mm, widely obovate, caudate-acuminate, abaxially hispid, hirtellous, glandular-puberulent, and minutely resin-dotted, adaxially glandular-puberulent, margins ciliate with stiff straight or curved trichomes0.5-1.5 mm; paleae 9-10 mm, 3-lobed, middle lobe long-acuminate, darkly pigmented, minutely hirtellous. Ray florets 12-34; laminas ±20 mm long, 5-8 mm wide, bright yellow.Disk florets many; corollas 6-6.5 mm, yellow, tube 1 mm, throat 3.5-4 mm, proximally swollen, distally cylindric, lobes ±1.5 mm, ovate, acute, tube and proximal bulge of throat puberulent with stiffly ascending acuminate trichomes, distal portion of throat and lobes glabrous; anthers ±4mm, reddish brown; shaft of style 4.5 mm, branches 2.5 mm, glabrous in proximal1 mm, distally densely hirtellous, reddish brown. Achenes ±3.5 mm, weakly compressed, gray-brown,densely covered with short, ascending trichomes; pappus scales 2.5-3 mm, lanceolate; 2n=34. Helianthus winterii is named after Robert F. Winter who has influenced many Californian botanists and natural historians.

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1 - H.T. Harvey and Associates, 7815 North Palm Ave., Fresno, CA, 93711, USA
2 - 357 Adler Ave., Clovis, CA, 93612, USA
3 - California State University, Department Of Biology, 2555 E. SAN RAMON AVE M/S SB73, FRESNO, CA, 93740-8034, USA


Presentation Type: Poster:Posters for Sections
Session: P
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM
Number: PSY031
Abstract ID:838

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