Rare Helianthus

 

This month's rare, possibly endangered plant is Helianthus arizonensis, the Arizona sunflower.  Here's the write-up for Facebook.

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Helianthus arizonensis

This month's rare plant is Helianthus arizonensis R.C. Jackson. iNaturalist shows a sighting near the Arizona border west of Quemado. It seems more frequently found in adjacent Arizona. Apparently it is found on dry, sandy soil at 4,000-7,000 ft elevation. It flowers June through August, so it should be out there. I guess seeing this plant in the wild will require more than a bicycle trip.

Our authority for this rare sunflower is Raymond Carl Jackson. His Wikipedia entry tells the story of his ties to New Mexico.

After three years of service in the U.S. Army Air Forces/U.S. Air Force, Jackson matriculated in 1949 at Indiana University, where he graduated with bachelor's degree in 1952 and master's degree in 1953. In 1953 he became a graduate student at Purdue University, where he graduated in 1955 with Ph.D. in botany. From 1955 to 1958 he was a faculty member and herbarium curator at the University of New Mexico. In New Mexico he studied the dessert annual Xanthisma gracile (synonym Haplopappus gracilis) and found that it has "n=2 chromosomes, the lowest number ever reported for a plant." From 1958 to 1971 he was a professor of botany at the University of Kansas, where in 1969 he was appointed chair of the botany department. There he was also the chair of the interdepartmental Ph.D. program in genetics. In 1971 Jackson become the chair of the department of biological sciences at Texas Tech University. There he resigned as chair in 1978, was appointed Paul Whitfield Horn Professor in 1980, became professor emeritus in 1997, and continued his research as Horn Professor Emeritus until he died in 2008.

Here's the description from NM Rare Plants. Herbaceous perennial with long creeping roots that function like rhizones; stems glabrous [smooth and hairless], glaucous [covered with a powdery bloom like that on grapes] 20-30 cm tall; leaves opposite, sessile, lanceolate, 6-7 cm long, 1.0-1.3 cm wide, tip acute, margins undulate, surface glabrous and glaucous, bluish-green; heads one to few; disk 1.0-1.8 cm in diameter; phyllaries lanceolate, ciliate on margins, glabrous to puberulent on backs, 2.0-2.7 mm broad; rays yellow, few, small; disk corollas yellow; pales acute, entire; pappus of 2 ovate scales; achenes about 3 mm long.

Helianthus ciliaris (blueweed) also has stems and leaves that are glaucous and bluish-green, but it is usually 40-70 cm tall and its disk corollas are red or reddish-tipped. Helianthus laciniatus has stems that are usually hispid [stiff coarse hairs or bristles] or strigose [short stiff adpressed hairs] and leaves that are glabrous to strigose and ashy green to light green in color.

This species is poorly known. Additional field searches are needed to determine range, abundance, habitat, reproduction and other important biological parameters. If you spot this one, post it to iNaturalist or get in touch with the folks at NM Rare Plants.