**Gaura drummondii (Onagraceae)**

**Scented Gaura, Drummond's Gaura**

**Description**. Herbaceous perennials, from extensive rhizomes, forming
mats or patches of erect to decumbent stems; stems 2-8 cm tall, often
branched at the base, usually with spreading hairs, sometimes villous or
glabrous. Leaves alternate, sessile to subsessile, blades 50-100 mm
long, 10-22 mm wide, elliptic to lanceolate, entire to sinuate-dentate.
Inflorescence 15-35 cm long, a terminal, bracteate spike, bracts 2-8 mm
long, 1-2 mm wide, narrowly lanceolate, the peduncle 3-10 cm long, .
Flowers radial, with a hypanthium 5-15 mm long; sepals four, 7-14 mm
long, less than 2 mm wide; petals four, 6-10 mm long, white, fading to
pink or red; stamens 8; ovary inferior, with 4 locules, style 12-25 mm
long, exserted, stigmatic branches 4. Fruit indehiscent, hard-walled,
7-13 mm long, ovoid, 4-ridged, furrowed betwen the ridges, upper portion
pyramidal, bulging at the base, base 3-5 mm long, with a thick terete
stalk about 1/4 the fruit in diameter. Seeds 2-8, 2-2.5 mm wide. In
California, flowering from May to September. (Munz 1959, Raven and
Gregory 1972, Wagner 1993)

NOTE: The name *G. odorata* Lagasca, was misapplied to this taxon in
California and elsewhere by earlier authors (e.g., Munz 1938, 1959,
1961). It has been treated as a synonym of *G. coccinea* (Raven and
Gregory 1972).

*Gaura drummondii* can be confused with two other naturalized species,
*G. coccinea* Pursh and *G. sinuata* Ser. Both species are also
rhizomatous perennials and have similar fruits, but *G. coccinea*
(including *G. odorata*) has stems that usually branch below ground and
well above the deep-seated rhizomes, and the petals are 3-7 mm long. The
inflorescence bracts are 0.5-1 mm wide (linear). *Gaura sinuata* has
generally has solitary stems borne along the rhizomes and the fruits are
are more slender (8-15 mm long, 1.5-3.5 mm wide, the stalk 2-8 mm long).

**Geographic** **distribution**. A native of southern Texas and northern
Mexico, *Gaura* *drummondii* has become naturalized only in California
and the southeastern United States (Munz 1938, 1961, Raven and Gregory
1972, Wagner 1993).

*Gaura drummondii* was first reported as naturalized by Munz (1959)
under the name *G*. *odorata**, ***but some records may have been
included under the name *G. sinuata*, which was reported as as early as
the 1930's (Munz 1935, Robbins 1940, Raven and Gregory 1972). *Gaura*
*drummondii* has been reported from Santa Cruz Island (Junak et al.
1997) and Santa Catalina Island (Raven and Gregory 1972), and in
mainland California occurs from Santa Cruz County south to San Diego
County (Raven and Gregory 1972).

The related species, *G. sinuata*, a native of the Great Plains, has
become naturalized elsewhere, including California, the southeastern
United States, and Mediterranean Europe (McGregor 1986, Raven and
Gregory 1972).

**Reproductive and vegetative biology**. Close relatives (including *G.*
*coccinea*) are self-compatible, but the genetic breeding system in G.
drummondii apparently has not been reported. *Gaura drummondii* (as most
species of the genus) is pollinated by small moths and butterflies
(Beerwinkle et al. 1996, Raven and Gregory 1972). No other literature
concerning its reproductive or vegetative biology was found.

**Ecological distribution**. It has been reported from cultivated
fields, pastures, roadsides, distrubed sites (Munz 1938, 1959, 1961,
Raven and Gregory 1972, Wagner 1993).

**Weed status.** *Gaura drummondii* 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), nor is it considered a noxious
weed by the State Dept. of Food and Agriculture (Anonymous 1996). It is
not listed for the United States in Lorenzi and Jeffery (1987).

**Microbial and insect pathogens**. No literature was found that
pertained to microbial pathogens or *Gaura* serving as a host of
detrimental microbial organisms. No literature was found that pertained
to insect pathogens or predation.

**Herbicide** **control**. No literature was found pertinent to
herbicidal control.

**Literature Cited**

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

Beerwinkle, K., T. Shaver, P. Lingren, and J. Raulston 1996. Free-choice
olfactometer bioassay system for evaluating the attractiveness of plant
volatiles to adult *Helicoverpa zea*. The Southwestern Entomologist. 21:
395-405.

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.

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.

McGregor, R. 1986. Onagraceae. pp. 498-526, In Great Plains Flora
Association. Flora of the Great Plains. University of Kansas, Lawrence.
1392 pp.

Munz, P. 1938. Studies in Onagraceae 11. A revision of the genus Gaura.
Bulletin, Torrey Botanical Club. 65: 105-122, 211-228.

Munz, P. 1959. A flora of California. University of California Press,
Berkeley. 1681 pp.

Munz, P. 1961. Onagraceae. pp. 208-262. In Lundell, C. Flora of Texas.
Volume 3. Texas Research Foundation, Renner, Texas. 433 pp.

Raven, P. and D. Gregory. 1972. A revision of the genus *Gaura*
(Onagraceae). Memoirs, Torrey Botanical Club 23: 1-96.

Robbins, W. 1940. Alien plants growing without cultivation in
California. Agricultural Experiment Station. Bulletin 637. University of
California, Berkeley. 128 pp.

Wagner, W. 1993. *Gaura*. P. 798. In Hickman, J. (ed.). The Jepson
manual: Vascular plants of California. University of California Press,
Berkeley. 1400 pp.