Diaperia prolifera

(Nuttall ex de Candolle) Nuttall

Trans. Amer. Philos. Soc., n. s. 7: 338. 1840

Common names: Big-head rabbit-tobacco
Basionyms: Evax prolifera Nuttall ex de Candolle
Treatment appears in FNA Volume 19. Treatment on page 462. Mentioned on page 461, 463.
Plants grayish green to silvery, 3–15 cm, sericeous to lanuginose. Stems mostly 2–10; branches proximal and distal (distal opposite or, sometimes, appearing alternate when unequal), rarely none. Leaves: largest 7–15 × 2–4 mm; capitular leaves subtending glomerules, also visible between and surpassing heads. Heads in strictly dichasiform or pseudo-polytomous arrays (sometimes appearing monochasiiform), cylindric to ± ellipsoid, 3.5–4.5 mm, heights 2–3 times diams. Receptacles broadly or narrowly conic, 0.4–0.6 mm or ± 0.9–1.1 mm, heights 0.5–0.7 or 2–2.4 times diams. Pistillate paleae imbricate, longest 2.5–4 mm. Staminate paleae ± 3, apices erect to somewhat spreading, ± plane. Functionally staminate florets 2–4; ovaries partly developed, 0.4–0.6 mm; corollas hidden in heads, actinomorphic, 1.4–2 mm, glabrous, lobes equal. Bisexual florets 0. Cypselae ± angular, obcompressed, mostly 0.9–1.2 mm.

Discussion

Varieties 2 (2 in the flora).

Intermediates between the two varieties of Diaperia prolifera occur where their ranges meet in central Texas and central Oklahoma. The strictly dichasiform or pseudo-polytomous branching pattern of D. prolifera is distinctive and diagnostic within the genus. Specimens of D. prolifera from introductions around a wool mill in South Carolina (G. L. Nesom 2004c, as Evax prolifera) are as yet undetermined to variety and are not included in the distributions below.

References

None.

Key

1 Plants grayish to greenish, loosely lanuginose; heads 4–40+ in largest glomerules; receptacle heights mostly 0.5–0.7 times diams.; capitular leaves usually ± spreading, scarcely involucral, not or scarcely carinate, pliant to somewhat rigid; distal branches mostly spreading to ascending; longest pistillate paleae 3.3–4 mm Diaperia prolifera var. prolifera
1 Plants silvery white, tightly sericeous; heads borne singly, or 2–3 in largest glomerules; receptacle heights mostly 2–2.4 times diams.; capitular leaves erect, involucral, proximally carinate, becoming indurate; distal branches strictly ascending to erect; longest pistillate paleae 2.5–3.2 mm Diaperia prolifera var. barnebyi