Helenium microcephalum explained

Helenium microcephalum is a North American perennial plant in the family Asteraceae, commonly known as smallhead sneezeweed. It is found in the southwestern and south-central United States and northern Mexico.^{[1] [2]}

Helenium microcephalum is an annual herb up to 120cm (50inches) tall, with wings running down the sides of the stems. Leaves are narrow and elliptical. One plant can have 300 or more small spherical or egg-shaped flower heads, generally no more than 12 mm (half an inch) in diameter. Each head can have 400 or more minuscule disc flowers 1.2– across, each yellow or yellow-green toward the bottom but brown or red toward the tip. There are also 7-13 red or yellow ray flowers.^[3]

Varieties^{[3] [2]}

• Helenium microcephalum var. microcephalum - Arizona, New Mexico, Oklahoma, Colorado, Texas, Coahuila, Nuevo León, Tamaulipas
• Helenium microcephalum var. ooclinium (A. Gray) Bierner - Texas, Coahuila, Chihuahua, Nuevo León, Durango, San Luis Potosí

Notes and References

1. http://bonap.net/MapGallery/County/Helenium%20microcephalum.png Biota of North America Program 2014 county distribution map
2. Turner, B. L. 2013. The comps of Mexico. A systematic account of the family Asteraceae (chapter 11: tribe Helenieae). Phytologia Memoirs 16: 1–100
3. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066855 Flora of North America, Helenium microcephalum de Candolle, 1836. Smallhead sneezeweed