Brassica rapa L. =Brassica rapa ssp. sylvestris =Brassica campestris  =Brassicaceae (Mustard Family Turnip Field Mustard

                                          February Photo

Plant characteristics:  Erect annual, 3-12 dm. tall, glaucous and quite glabrous except for scattered hairs on lower leaves; these petioled, plus/minus pinnatifid or lobed, 1-2 dm. long; upper sessile, auriculate-clasping, lance-oblong, subentire, glabrous; pedicels (stalk of a single flower) spreading, 1-2 cm. long, sepals narrow oblong, yellowish, 4-5 mm. long; petals yellow, spatulate, 6-8 mm. long; siliques (seed pods) terete, 2-5 cm. long stout with a stout beak an additional 1-l.5 cm. long; seeds l.5-2 mm. thick, dark, reticulate.

Habitat: Orchards, waste places throughout Calif., below 1500 m. Jan.-May

Name: Brassica is the Latin name for cabbage. (Munz, Flora So. Calif. 276).  Campestris, of the field.  (Jaeger 44).

General:  Common in the study area, first mustard to bloom in the spring.  Photographed on the east side of the Delhi Ditch and the Santa Ana Heights Flats.  (my comments).  This widespread weed is introduced from Europe and occurs in the North Central and Eastern States.  (Robbins et al. 208).      B. rapa has tuberous roots and is the turnip.  (ref. not recorded).     Brassica rapa has been known to accumulate free nitrates in quantities capable of causing death or distress in cattle.  (Fuller 385).       A Danish team of researchers has determined that some genetically engineered plants can pass those new genes to plants that belong to the same general family.  "This is a problem that could have serious consequences all around the world, depending on the crop, the location of its wild relatives, and the gene involved." said Gene Rissler, a biotechnology expert at the Union of Concerned Scientists, a nonprofit lobbying group.  The plant geneticists at the Riso National Laboratory in Roskilde, Denmark, did their experiments with oilseed rape, which is grown widely in Canada and Europe to produce canola oil and Brassica campestris, a closely related weed in the mustard family.  The researchers found that the two plant species will cross fertilize each other and, within as few as two generations, the resulting crossbreeds not only contained the new gene, but were capable of passing on the new trait to subsequent generations.  Monsato Co., a leader in agricultural bioengineering, has developed a variety of herbicide-resistant canola, which it is testing in Europe.  The resistant weeds that have evolved spontaneously as a consequence of its field experiments are "not very fertile," a company spokeswoman said. Several U.S. biotechnology experts said the recent finding in Denmark was no reason for a blanket of condemnation on the products from biotechnology's new horn of plenty.  (Hotz, Robert Lee.  "Weeds Reap What Science Sows."  Los Angeles Times, March 6, 1996, Orange County Edition: A3.       About 100 species of Europe, Asia and North Africa; many like cabbage, broccoli, cauliflower, turnip, etc., are important food plants.  (Munz, Flora So. Calif. 276).

Text Ref:  Abrams, Vol. II 274; Hickman, Ed. 406; Munz, Flora So. Calif. 276; Roberts 15.

Photo Ref:  Feb 2 84 # 2,3.

Identity: by R. De Ruff, confirmed by F. Roberts.  

First Found:  February 1984.

Computer Ref:  Plant Data 2

Have plant specimen.

Last edit 5/17/05.  

                                 February Photo                                                                          February Photo