Heliotropium tenellum (Nutt.) Torr.

Heliotropium tenellum plant

Family - Boraginaceae

Stems - To +/-25cm tall, erect, branching, herbaceous, terete, with a fairly dense appressed grey pubescence (giving the stems a grey appearance), from a taproot and some spreading roots, often becoming purplish in strong sun.

Heliotropium tenellum stem

Leaves - Alternate, short-petiolate to sessile, linear, to 4cn long, 3-5mm broad. Petioles to 2-3mm long. Blades deep green above, with appressed pubescence, with a single midrib, entire, acute. Margins often revolute in strong sun.

Inflorescence - Terminal bracteate loose cymes. Flowers sessile.

Heliotropium tenellum inflorescence

Flowers - Corolla white, 5-lobed, 5-6mm broad, salverform. Corolla tube canescent externally, 3mm long. Corolla lobes rounded, glabrous internally, to 2mm broad. Stamens 5, adnate at the base of the corolla tube, included. Filaments wanting. Anthers to 1mm long, surrounding the pistil. Ovary superior, globose, green, .3mm in diameter. Style minute. Stigma subconic, .6mm long. Sepals 5, equal to unequal, with the same pubescence as the stem, linear-oblong, to 5-6mm long, 1-2mm broad, entire.

Heliotropium tenellum flower

Flowering - June - August.

Habitat - Limestone glades and rocky prairies.

Origin - Native to U.S.

Other info. - This little species is common in the Ozark region of Missouri. The plant is a characteristic glade species. H. tenellum is an easy species to ID because of its canescent stems, small white flowers, and habitat.

Photographs taken at the Peck Ranch Wildlife Refuge, Carter County, MO., 7-12-03.


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