Annuals, 16-50+ cm.
Caudices none.
Stems 1-10, erect or ± decumbent, leafy, unbranched or branched distally.
Leaves basal and cauline, ± hairy, ± gland-dotted; basal blades spatulate to oblanceolate, entire or with 2-6 teeth or lobes; proximal cauline blades narrowly spatulate or oblanceolate to linear-oblanceolate, entire or with 2-6 teeth or lobes; mid blades oblanceolate to linear-oblanceolate to linear, 0.9-9.5(-16) mm wide, entire or with 1-2 teeth or lobes; distal blades narrowly oblanceolate to linear-oblanceolate to linear, entire or with 1-2 teeth or lobes.
Heads 8-50(-80) per plant, borne singly or in corymbiform arrays.
Peduncles 8-29 cm, ± hairy.
Involucres 5-10 × 7-15 mm.
Outer phyllaries 8-21, 2.4-5.5 mm, margins 0-0.2 mm wide, not scarious or scarious, abaxial faces ± hairy.
Ray florets 9-25; corollas 8.2-16.8 mm.
Disc florets 50-200+; corollas yellow, 1.6-3 mm.
Cypselae 1.5-2.6 mm;
pappi of 4-8 obovate, often aristate scales 1-2.5 mm. Plants of
Tetraneuris linearifolia morphologically intermediate between the two varieties are found in Bee, Duval, Live Oak, and McMullen counties, Texas.
