**Verbascum thapsus L. (Scrophulariaceae)**

**Common Mullein, Woolly Mullein**

**Description**. Herbaceous, monocarpic, usually biennial, 3-20 dm tall;
stems erect, stout, winged at the base of the cauline leaves. Basal
leaves in a rosette, petiolate, the blades 8-50 cm long, 2.5-14 cm wide,
oblanceolate to obovate, cauline alternate, sessile, decurrent, reduced
upwards, the blades 1.5-15 cm long, oblanceolate, yellowish
woolly-tomentose, margins entire, apices acute to obtuse, the bases
acute to tapered. Inflorescence a terminal, dense spike. Flowers
slightly bilateral to radial, calyx 5-12 mm long, lobes five,
lanceolate; corolla 12-30 mm wide, rotate, yellow, the lobes ciliate;
stamens 5, all fertile, unequally inserted, the lower filaments
glabrous, the upper yellow-villous; ovary superior. Fruit a capsule,
7-10 mm long, globose, densely tomentose, ovoid; seeds many. In
California, flowering from June to October. (Fernald 1950, Gleason and
Cronquist 1991, Holmgren 1984, Munz 1959, Pennell 1951, Wagner et al.
1990, Webb 1972, Webb et al. 1988, Welsh et al. 1987, Wetherwax 1993).

Webb (1972) recognized three subspecies in Europe, based on variation in
filament pubescence and leaf decurrence, but the three taxa are not
easily distinguished in North America (Gleason and Cronquist 1991,
Holmgren 1984)

**Note:** Common mullein produces iridoid glycosides, which may
influence palatability by insects, and also is known as a source of
medicinal herbal extracts (e.g., Filippini et al. 1990, McCutcheon et
al. 1995).

**Geographic distribution**. A native of Eurasia, common mullein has
become naturalized throughout North America, Chile, Hawaii, Australia,
and New Zealand. (Holmgren 1984, 1986, Montenegro et al. 1991, Munz
1959, Wagner et al. 1990, Webb et al. 1988).

Common mullein was first collected in California (Sacramento County) in
the 1850s (Brandegee 1901) and from southern California between 1906 and
1918 (Parish 1920). It has been reported only from Santa Cruz Island
(Junak et al. 1997), but is widespread on mainland California (Anonymous
1998, Weatherwax 1993).

**Reproductive and vegetative biology**: *Verbascum thapsus* is
self-compatible, but largely outcrossing (Darwin 1876). The flowers are
pollinated principally by small bees in Great Britain and Europe
(Proctor et al. 1996). Seed dispersal is passive and generally limited
to ca. 4 meters (Salisbury 1961). Seeds require light for germination,
which is enhanced by cold temperatures during the first season after
dispersal (Baskin and Baskin 1981, Gross 1985, Vanlerberghe and Van
Assche 1986). However, ungerminated seeds may enter a longer phase of
dormancy by exposure to warm temperatures and can retain high levels of
viability (up to 95%) for at least 17 years (Baskin and Baskin 1981,
Burnside et al. 1996). Seed germination is enhanced by cultivation, soil
movements by subterranean rodents, and is suppressed by leaf litter
(Bosy and Reader 1995, Gross 1980, Gross and Werner 1982, Semenza et al.
1978).

Common mullein is generally referred to as a biennial, but individual
plants may live longer than 3 (i.e., triennial) years (Gross 1981,
Reinartz 1984a,b,c). In some populations from warm temperate climates,
plants lived only 1 year prior to reproduction, but in others triennials
predominated in populations followed from germination to reproduction
(Reinartz 1984a,b,c). Common mullein shows a broad range of ecotypic
variation for life history characteristics, including rosette size,
rosette longevity, reproductive capacity, and timing of reproduction
(Reinartz 1984a,b,c). Growth during the vegetative phase depends on
available nutrients and light; reproductice capacity increases with
increasing rosette size (Abrahamson and Caswell 1982). Compared to other
monocarpic species, Reinartz (1984b) reported that common mullein has a
relatively low seed production (25-40% of ovule number).

**Ecological distribution**. Common mullein occurs in disturbed open
sites, fallow fields, and along roadsides (Gleason and Cronquist 1991,
Holmgren 1984, Mitich 1989, Munz 1959, Reinartz 1984a, Welsh et al.
1987).

**Weed status.** *Verbascum thapsus* is not considered a serious noxious
weed in agricultural or horticultural practice, at least at a global
level (not listed by Holm et al. 1977), but it has been listed for the
United States by Lorenzi and Jeffery (1987). However, it is considered
as a noxious weed by the State Dept. of Food and Agriculture (Anonymous
1996), especially in eastern California sagebrush associations and
pinyon-juniper woodlands..

**Microbial and insect pathogens.** No literature was found that
reported microbial or insect pathogens of common mullein.

**Herbicide Control**. Lorenzi and Jeffery (1987) recommended mechnical
removal of rosettes or treatment with either 2,4-D or glyphosate. No
other literature was found pertinent to herbicide control.

**Literature Cited**

Abrahamson, W. and H. Caswell. 1982. On the comparative allocation of
biomass, energy, and nutrients in plants. Ecology. 63: 982-991.

Anonymous. 1996. Exotic pest plants of greatest ecological concern in
California as of August 1996. California Exotic Pest Plant Council. 8
pp.

Anonymous. 1998. California county flora database version 2, Santa
Barbara Botanic Garden and USDA National Plants Data Center, Santa
Barbara and New Orleans. URL = plants.usda.gov

Baskin, J. and C. Baskin. 1981. Seasonal changes in germination
responses of buried seeds of *Verbascum thapsus* and *Verbascum*
*blattaria* and ecological implications. Canadian Journal of Botany. 59:
1769-1775.

Bosy, J. and R. Reader. 1995. Mechanisms underlying the suppression of
forb seedling emergence by grass (*Poa pratensis*) litter. Functional
Ecology. 9: 635-639.

Brandegee, K. 1901. *Verbascum* in California Zoe 5: 138.

Burnside, O., R. Wilson, S. Weisberg, and K. Hubbard. 1996. Seed
longevity of 41 weed species buried 17 years in eastern and western
Nebraska. Weed Science 44: 74-86.

Darwin, C. 1876. The effects of cross and self fertilization in the
vegetatble kingdom. John Murray, London.

Fernald, M. 1950. Gray's Manual of Botany. Eighth Edition. American Book
Company, New York. 1632 pp.

Filippini, R., E. Cappelleti, and R. Caniato. 1990. Botanical
identification of powdered plant drugs. *Verbascum* flowers.
International Journal of Crude Drug Research. 28: 129-133.

Gleason, H. and A. Cronquist. 1991. Manual of the vascular plants of
northeastern United States and Adjacent Canada. 2nd edition. New York
Botanic Garden, Bronx. 910 pp.

Gross, K. 1980. Colonization by *Verbascum thapsus* (Mullein) of an
old-field in Michigan: experiments on the effects of vegetation. Journal
of Ecology. 68: 919-927.

Gross, K. 1981. Predictions of fate from rosette size in four
\"biennial\" plant species: *Verbascum thapsus*, *Oenothera biennis*,
*Daucus carota* , and *Tragopogon dubius*. Oecologia. 48: 209-213.

Gross, K. 1985. Effects of irradiance and spectral quality on the
germination of *Verbascum thapsus* L. and *Oenothera biennis* L. seeds.
The New Phytologist. 101: 531-541.

Gross, K. and P. Werner. 1982. Colonizing abilities of \"biennial\"
plant species in relation to ground cover: implications for their
distributions in a successional sere -*Verbascum thapsus*, *Oenothera
biennis,* *Daucus carota*, *Tragopogon dubius*, Michigan. Ecology. 63:
921-931.

Holm, L., D. Plucknett, J. Pancho, and J. Herberger. 1977. The world's
worst weeds: distribution and ecology. University Press of Hawaii,
Honolulu. 609 pp.

Holmgren, N. 1984. Scrophulariaceae. pp. 344-506. In Cronquist et al.
Intermountain flora. Volume 4. New York Botanical Garden, Bronx, New
York. 573 pp.

Holmgren, N. 1986. Scrophulariaceae. pp. 751-797. In Great Plains Flora
Association. 1986. Flora of the Great Plains. University of Kansas,
Lawrence. 1392 pp.

Junak, S., S. Chaney, R. Philbrick, and R. Clark. 1997. A checklist of
vascular plants of Channel Islands National Park. Southwest Parks and
Monuments Association, Tucson, AZ. 43 pp.

Lorenzi, H. and L. Jeffery. 1987. Weeds of the United States and their
control. Van Nostrand Company, New York. 355 pp.

McCutcheon, A., T. Roberts, E. Gibbons, S. Ellis, L. Babiuk, R. Hancock,
and G. Towers. 1995. Antiviral screening of British Columbian medicinal
plants. Journal of Ethnopharmacology. 49: 101-110.

Mitich, L. 1989. Common mullein-the roadside torch parade. Weed
Technology. 3: 704- 705.

Montenegro, C., S. Teillier, P. Arce, and V. Poblete. 1991. pp. 103-114.
In Groves, R. and F. Di Castri. Biogeography of Mediterranean invasions.
Cambridge University Press, Cambridge. 485 pp.

Munz, P. 1959. A flora of California. University of California Press,
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Parish, S. 1920. The immigrant plants of southern California. Bulletin,
Southern California Academy of Sciences 19: 3-30.

Pennell, F. 1951. Scrophulariaceae. pp. 686-859. In Abrams, L.
Illustrated flora of the Pacific states. Volume 3. Geraniaceae to
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pp.

Proctor, M., P. Yeo, and A. Lack. 1996. The natural history of
pollination. Timber Press, Portland, Oregon. 479 pp.

Reinartz, J. 1984a. Life history variation of common mullein (*Verbascum
thapsus*). I. Latitudinal differences in population dynamics and timing
of reproduction. Journal of Ecology. 72: 897-912.

Reinartz, J. 1984b. Life history variation of common mullein (*Verbascum
thapsus*). II. Plant size, biomass partitioning and morphology. Journal
of Ecology. 72: 913-925.

Reinartz, J. 1984c. Life history variation of common mullein (*Verbascum
thapsus*). III. Differences among sequential cohorts. Journal of
Ecology. 72: 927-936.

Richards, A. 1978. The pollination of flowers by insects. Linnean
Society Symposium Series 6: 1-213. Academic Press, London.

Robbins, W. 1940. Alien plants growing without cultivation in
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California, Berkeley. 128 pp.

Salisbury, E. 1961. Weeds and aliens. Collins Publishers, London.

Vanlerberghe, K. and J. Van Assche. 1986. Dormancy phases in seeds of
*Verbascum thapsus* L. Oecologia. 68: 479-480.

Semenza, R., J. Young, and R. Evans. 1978. Influence of light and
temperature on the germination and seedbed ecology of common mullein
(*Verbascum thapsus*). Weed Science 26: 577-581.

Wagner, W., D. Herbst, and S. Sohmer. 1990. Manual of the flowering
plants of Hawaii. 1853 pp.

Webb, C., W. Sykes, and P. Garnock-Jones. 1988. Flora of New Zealand.
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Welsh, S., N. Atwood, S. Goodrich, and L. Higgins. 1987. A Utah Flora.
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Wetherwax, M. 1993. *Verbascum*. p. 1064. In Hickman, J. (ed.). The
Jepson manual: Vascular plants of California. University of California
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