Pseudognaphalium leucocephalum

(A. Gray) Anderberg

Opera Bot. 104: 147. 1991.

Common names: White rabbit-tobacco
Basionym: Gnaphalium leucocephalum A. Gray Smithsonian Contr. Knowl. 5(6): 99. 1853
Treatment appears in FNA Volume 19. Treatment on page 423. Mentioned on page 416, 422.

Biennials or short-lived perennials, 30–60 cm; taprooted. Stems densely and persistently white-tomentose, usually with stipitate-glandular hairs protruding through tomentum. Leaf-blades (crowded, internodes mostly 1–3, sometimes to 10 mm) linear-lanceolate, 3–7 cm × 1–5 (–6) mm, bases subclasping, not decurrent, margins strongly revolute, faces bicolor, abaxial densely white-tomentose, adaxial green, densely stipitate-glandular. Heads in corymbiform arrays. Involucres broadly campanulate, 5–6 mm. Phyllaries in 5–7 series, bright white (opaque, dull), oblong to oblong-ovate, glabrous. Pistillate florets 66–85. Bisexual florets (6–14, California) 29–44. Cypselae ridged, smooth. 2n = 28.


Phenology: Flowering (Jul–)Aug–Nov(–Dec).
Habitat: Sandy or gravelly slopes, stream bottoms, arroyos, areas of oak-sycamore, oak-pine, to pine woodlands, commonly in riparian vegetation
Elevation: 50–2100 m

Distribution

V19-694-distribution-map.gif

Ariz., Calif., N.Mex., Mexico (Baja California), Mexico (Baja California Sur), Mexico (Chihuahua), Mexico (Durango), Mexico (Sinaloa), Mexico (Sonora)

Discussion

Pseudognaphalium leucocephalum is similar to P. viscosum, which has shiny, hyaline, ovate-lanceolate phyllaries, 200–250 pistillate florets, (13–)16–29 bisexual florets, and papillate-roughened cypselae. Some plants of P. leucocephalum also appear to approach P. biolettii in general appearance, and it is possible that some of them may represent hybrids. Plants of P. biolettii differ from P. leucocephalum in their typically eglandular stems, broader, basally ampliate, clasping, more widely spaced, and less densely glandular leaves, and thinner, shiny phyllaries.

Selected References

None.

Lower Taxa

None.
white +  and gray +
white-tomentose +
stipitate-glandular +
scarious +
mostly ovate +  and lanceovate or linear +
indeterminate +  and determinate +
Guy L. Nesom +
(A. Gray) Anderberg +
subclasping +
not decurrent +
Gnaphalium leucocephalum +
compound +  and simple +
mostly narrowly lanceolate;oblanceolate +
5-ribbed +, 3-ribbed +  and 2-ribbed +
muriculate +, papillate +  and smooth +
White rabbit-tobacco +
actinomorphic +
Ariz. +, Calif. +, N.Mex. +, Mexico (Baja California) +, Mexico (Baja California Sur) +, Mexico (Chihuahua) +, Mexico (Durango) +, Mexico (Sinaloa) +  and Mexico (Sonora) +
50–2100 m +
papillate-roughened +
winged +  and beaked +
dispersed +
Sandy or gravelly slopes, stream bottoms, arroyos, areas of oak-sycamore, oak-pine, to pine woodlands, commonly in riparian vegetation +
protruding +
stipitate-glandular +
singly +  and aggregated +
indeterminate +
homogamous +  and heterogamous +
each +  and sessile +
0.3 cm3 mm <br />0.003 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
campanulate +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
3 cm30 mm <br />0.03 m <br /> (7 cm70 mm <br />0.07 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
cauline +  and basal +
rarely lanceovate +  and lanceolate +
2-carpellate +
persistent +
Flowering (Jul–)Aug–Nov(–Dec). +
bearing subulate enations +, hairy +  and bristly +
conic;more or less columnar +
4 +  and 6 +
exalbuminous +
decumbent +  and procumbent +
appendaged +  and truncate +
papillate +
Compositae +
Pseudognaphalium leucocephalum +
Pseudognaphalium +
species +
150 cm1,500 mm <br />1.5 m <br /> (200 cm2,000 mm <br />2 m <br />) +
perennial +, short-lived +  and biennial +
30 cm300 mm <br />0.3 m <br /> (60 cm600 mm <br />0.6 m <br />) +
shrub +  and subshrub +