7. Leibnitzia Cassini in F. Cuvier, Dict. Sci. Nat. ed. 2. 25: 420. 1822.
[For G. W. Leibnitz, 1646–1716, philosopher, political advisor, mathematician, and scientist]
Guy L. Nesom
Perennials, 5–60+ cm (fibrous-rooted; stems 1–11, scapiform, sometimes bracteate). Leaves basal; petiolate; blades elliptic to obovate, oblanceolate, or lyrate, bases cuneate, margins usually sinuately lobed to dentate, sometimes entire or pinnatifid, abaxial faces thinly gray-tomentose [covered with dense wool], adaxial faces glabrous or glabrescent (vernal leaves appearing after or concurrently with first heads). Heads quasi-radiate (see florets), borne singly (erect in bud, flowering, and fruit). Involucres cylindric to campanulate, 9–20+ mm. Phyllaries in 3–4+ series, lanceolate to lance-linear, unequal, apices acute to acuminate. Receptacles flat to convex, foveolate to alveolate, glabrous, epaleate. Florets: outer 6–15 pistillate, fertile, corollas usually pinkish to purplish (vernal with relatively broad laminae ± equaling tubes and bifurcate inner lips, autumnal with relatively narrow, greatly shortened laminae); inner 6–20+ florets bisexual, fertile, corollas usually whitish (vernal funnelform, 2-lipped, lobes 5, recurved or coiled, autumnal narrowly tubular, barely 2-lipped or nearly actinomorphic, lobes 5, erect); anther basal appendages entire, apical appendages lanceolate; style branches relatively short, apices rounded to truncate (abaxial faces pilose). Cypselae ± fusiform (somewhat flattened), distally ± constricted into relatively broad necks or narrow beaks 1/5–1/3+ lengths of bodies, ribs [5–]8+, faces strigose to hispid (hairs duplex, relatively long, apices sharp-pointed), not glandular; pappi of 50–80+ stramineous, barbellulate bristles. x = 23.
Species 6 (1 in the flora). United States, Mexico, Asia.
Two species of Leibnitzia occur in North America (one is restricted to western Mexico); the remaining four are Asian. The species are characterized by dimorphic heads: those produced in the spring appear before or with the leaves and are chasmogamous and quasi-radiate; the fall forms appear after the leaves and are cleistogamous (not exposing any florets but setting full fruit). The florets also differ morphologically between the chasmogamous and cleistogamous heads. The widespread American species (L. lyrata) has been placed within Chaptalia; species of Leibnitzia are distinguished from all Chaptalia species by the slender, sharp-pointed hairs on their cypselae.
SELECTED REFERENCE
Nesom, G. L. 1983. Biology and taxonomy of American Leibnitzia (Asteraceae). Brittonia 35: 126–139.
