Non-technical Description: Slender false-foxglove is a glabrous annual herb with multi-branched stems 20-50 cm tall. Stems are reddish to dark green when fresh, but turn black when dried in a plant press. Leaves are opposite, ascending, linear, entire, 3-7 cm long and 1-2 mm wide and often have clusters of smaller leaves in their axils. The inflorescence of 1-several racemes has 1-12 flowers. Bracts are leaf-like and progressively reduced upwards. The 5-lobed corolla is pink or purple, 10-15 mm long, slightly 2-lipped and funnel-shaped and glabrous with ciliate margins. Sepals are united into a 5-lobed calyx 3.5-5.5 mm long. Anthers are sparsely hairy, arranged in a straight line, and 1.5-2.2 mm long. Fruits are globe-shaped capsules 4-6 mm long (Great Plains Flora Association 1986).
Similar Species: Linaria canadensis has a blue, two-lipped corolla with a slender spur. Mimulus spp. have a strongly two-lipped corolla and flowers that are often yellow or pink-flowered (Dorn 2001).
Habitat: Found in moist woods and prairies along streams, lakeshores, and ditches (Great Plains Flora Association 1986).
References: Dorn, R.D. 2001. Vascular Plants of Wyoming, 3rd ed. Mountain West Publishing, Cheyenne, WY. 412 pp; Great Plains Flora Association. 1986. Flora of the Great Plains. Univ. Kansas Press, Lawrence, KS; Pennell, F.W. 1929. Agalinis and allies in North America II. Proceedings Philadelphia Academy Natural Sciences 81:111-249.
Author: Walter Fertig, Moenave Botanical Consulting, Kanab, UT. April 2017.
From Flora of Indiana (1940) by Charles C. Deam
This variety is found in habitats similar to var. macrophylla.
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Diagnostic Traits: Capsules similar in size to those of var. macrophylla, but leaves less wide; enhanced development of axillary fascicles.