Big Bend Ringstem (Anulocaulis eriosolenus)

Overview, Coahuila, Mexico. Photograph by Wynn Anderson.

 

Flowers in bloom and post-bloom, Coahuila, Mexico. Photographs by Wynn Anderson.

• Common English Names: Big Bend Ringstem
• Common Spanish Names: None known
• Scientific Name: Anulocaulis eriosolenus (ann-noo-low-CALL-us air-ree-oh-SOL-en-us)
• Family: Nyctaginaceae (Four-O'clock Family)
• Geographic Range: On slopes of sandy, gravelly, gypsum, or calcareous soils in the Big Bend region of Texas, adjacent Coahuila and in south central Coahuila, Mexico.
• Description: Herbaceous annual or short lived perennial with large coarse green, sometimes purplish tinged, basal leaves and with erect stems, 2-6' tall, holding scattered, mostly solitary, pink to rose-magenta short-tubed flowers which elongate markedly after blooming. A nocturnal bloomer, the flowers opening at dusk and closing by mid-morning.
• Notes: Ringstems are named for the often pronounced, viscid, sticky, sap-like ring that encircles the elongated stems between upper joints below the inflorescence of this and several other members of the plant family. The purpose of this feature is unknown but it often traps and holds small insects as well as dust and tiny particles of wind-blown debris. This may be a means of providing additional nutrients of some form at flowering time.

Last Update: 29 Sep 2013