Lessingia in Flora of North America @ efloras.org

209. Lessingia Chamisso, Linnaea. 4: 203, plate 2, fig. 2. 1829.

[For C. F. Lessing, 1809–1862, German-born botanist, his nephew K. F. Lessing, and grandfather G. E. Lessing]

Staci Markos

Annuals, mostly 2–90 cm; taprooted. Stems erect or decumbent, simple or branched from bases or distally, glabrous or villous to woolly. Leaves basal and/or cauline (basal rosettes sometimes withering by flowering); alternate; petiolate or sessile; blades 1-nerved, ovate or obovate to lanceolate, linear, or subulate (bases sometimes clasping), margins entire or dentate to pinnately lobed, abaxial faces glabrous or sparsely tomentose to woolly, sometimes stipitate-glandular. Heads discoid (or ± radiant, corollas of outer florets sometimes enlarged), borne singly or in ± corymbiform arrays (terminal or sessile to subsessile in axils of leaves). Involucres hemispheric, obconic, campanulate, or narrowly cylindric, 4–13 mm diam. Phyllaries 10–55 in 4–8 series, erect or recurved (green to purple), 1-nerved (flat), oblong, ovate, or lanceolate, unequal, herbaceous, scarious, or rarely cartilaginous (apices obtuse to acute), faces glabrous or villous to woolly, sometimes stipitate-glandular. Receptacles slightly convex, pitted, epaleate. Ray florets 0. Disc florets 3–40, bisexual, fertile; corollas white, pink, lavender, or yellow, tubes shorter or longer than funnelform to tubular throats (each with or without colored band inside, limbs frequently palmately expanded in peripheral florets), lobes 5, erect or spreading, lanceolate; style-branch (linear) appendages lanceolate (0.3–1.3 mm) or truncate-penicillate (0.1–0.4 mm). Cypselae (white to tan or mottled purple-brown) cuneiform to linear, not compressed, smooth or obscurely 5–10-nerved, faces puberulent to pilose; pappi persistent, of 3–55, distinct or basally connate, tan to reddish, barbellate, apically attenuate bristles in 1–2 series, sometimes forming coronas. x = 5, 6.

Species 12 (12 in the flora): w North America, nw Mexico.

In gland-bearing lessingias, the glands may be stipitate and/or sessile (gland-dotted, sometimes in pits) and may be found on stems, leaves, and/or phyllaries. They are seldom restricted to the faces of leaves or phyllaries and are usually most prominent on leaf and/or phyllary margins.

SELECTED REFERENCES

Howell, J. T. 1929. A systematic study of the genus Lessingia Cham. Univ. Calif. Publ. Bot. 16: 1–44. Markos, S. 2005. Taxonomic changes in Lessingia (Compositae: Astereae). Madroño 52: 60–61. Markos, S. and B. G. Baldwin. 2001. Higher-level relationships and major lineages of Lessingia (Compositae, Astereae) based on nuclear rDNA internal and external transcribed spacer (ITS and ETS) sequences. Syst. Bot. 26: 168–183. Spence, W. L. 1963. A Biosystematic Study of the Genus Lessingia Cham. (Compositae). Ph.D. thesis. University of California, Berkeley.

1 Corollas yellow (sometimes pink or suffused with purple in peripheral florets of L. tenuis) (2)

+ Corollas white, pink, or lavender (5)

2 (1) Style-branch appendages lanceolate, 0.3–1.3 mm, corolla tubes without brown-purple band inside 1 Lessingia glandulifera

+ Style-branch appendages truncate-penicillate, 0.1–0.4 mm, corolla tubes with brown-purple band inside (3)

3 (2) Plants eglandular or phyllaries sparsely gland-dotted (San Francisco peninsula, California) 2 Lessingia germanorum

+ Plants ± glandular (4)

4 (3) Cauline leaves sometimes gland-dotted; phyllary apices purple; corollas yellow (occasionally pink or suffused with purple in peripheral florets) 3 Lessingia tenuis

+ Cauline leaves gland-dotted; phyllary apices usually green, rarely purple; corol-las yellow 4 Lessingia pectinata

5 (1) Phyllaries usually glabrous, rarely villous, sometimes stipitate-glandular or gland-dotted (6)

+ Phyllaries villous to tomentose or woolly, sometimes gland-dotted as well (8)

6 (5) Basal leaves usually persistent at flowering; cauline leaves stipitate-glandular; involucres hemispheric to campanulate; corollas lavender (never white) 5 Lessingia ramulosa

+ Basal leaves usually withering by flowering; cauline leaves sometimes stipitate-glandular; involucres cylindric to broadly obconic; corollas white (occasionally pale lavender) (7)

7 (6) Cauline leaves gland-dotted (in pits) and sometimes stipitate-glandular; style-branch appendages usually lanceolate, sometimes truncate-penicillate 6 Lessingia nemaclada

+ Cauline leaves usually eglandular, sometimes sparsely stipitate-glandular; style-branch appendages truncate-penicillate 7 Lessingia micradenia

8 (5) Stems decumbent; apices of phyllaries green; inner phyllaries cartilaginous; pappi pink to red 8 Lessingia nana

+ Stems erect; apices of phyllaries green or purple; inner phyllaries scarious; pappi white to tan (9)

9 (8) Cauline leaves eglandular (10)

+ Cauline leaves gland-dotted (in pits, rarely stipitate-glandular in L. virgata, glands sometimes obscured by tomentum) (11)

10 (9) Basal leaves withering by flowering; involucres 4–8 mm; style-branch appendages truncate-penicillate; pappi usually shorter than cypselae (except in Sonoma County, California) 9 Lessingia arachnoidea

+ Basal leaves persistent at flowering; involucres (5–)8–13 mm; style-branch appendages lanceolate; pappi equaling or longer than cypselae 10 Lessingia hololeuca

11 (9) Cauline leaf faces glabrous or villous to tomentose; heads usually at ends of branchlets; florets 6–25; corollas lavender (never white) 11 Lessingia leptoclada

+ Cauline leaf faces villous to woolly; heads usually in axils of leaves; florets 3–6; corollas usually white, sometimes pale lavender 12 Lessingia virgata

List of lower taxa