Convolvulus arvensis  L.   Convolvulaceae (Morning-Glory Family)   Eurasia   Bindweed    Wild Morning-Glory     Orchard Morning-Glory

                                        July Photo

Plant Characteristics:  Perennial, with a long taproot, herbage glabrous to pubescent; lf. blades oblong-sagittate to ovate to rounded at apex, mostly 1.5-3.5 cm. long; petioles slender, shorter than the blades; peduncles commonly 1 fld., sometimes 2-3 fld.; peduncle 1-2 in. long with a pair of subulate bracts 2-4 mm. long near the middle; corolla white, purplish outside, open-funnelform and neither lobed nor angled.       Not mentioned in Munz, but a characteristic I have noticed are the purple stripes on the back of the corolla.  (my comment).

Habitat:  Deep rooted and troublesome weed in orchards and fields; waste places below 5000 ft.

Name: Latin, convolvere, to entwine. (Munz, Calif. Flora 375).  New Latin, arvensis, of or belonging to the field.  (Jaeger 26).

General:  Occasional in the study area.  Photographed on the North Star Flats and along Back Bay Dr. near the old Salt Works dike.  (my comments).      The root is a purgative, hydragogue, cathartic, and diuretic.  (Coon 230).      The plant has an adverse effect on agriculture and is widely distributed throughout the state.  Control must be figured into the cost of production.  Up to 100% crop loss from this weed could be anticipated in the cotton crop without control.  (FREMONTIA, A Journal of the California Native Plant Society.  July 1985.  Author and title of article not recorded).      The root system of this plant is characterized by the production of annual laterals in great numbers.  These laterals develop adventitiously throughout the length of the taproot and its branches, and permeate the soil in all directions.  Most of them die at the end of the season and are replaced by new ones each year; but any which have become favorably situated may make more than average growth and become so well developed that they persist as permanent branches.  It is by means of these persistent laterals that spreading in a horizontal direction is accomplished.  Shoot buds arise on these horizontal laterals and develop into rhizomes which, reaching the surface, establish new crowns.  The unusual ability of the morning-glory plant to reproduce vegetatively is related to the form of its underground structures.  The relatively large storage capacity of the root necessitates the existence of many living cells in close relation with a large supply of food, and an efficient system for absorbing mineral nutrients.  These conditions favor bud formation, which is the most characteristic habit of the plant.  Favorable growing conditions stimulate intense activity, and these buds may be produced by dozens or even hundreds, especially during warm weather and after a cultivation that has destroyed the top growth.  The ability to produce buds, together with the food reserve of the root, favors vegetative reproduction and makes the plant persistent.  The dense foliage and twining growth enable the plant to choke out competitors and present difficulties to thorough spraying.   Although the species of Convolvulus contain a toxic milky juice in the roots, no well-authenticated cases of poisoning have been reported.  There is evidence, however, that "hair-balls" in sheep are largely composed of fibers of these plants. (Robbins et al. 340,343).      C. arvensis has been found to accumulate free nitrates in quantities capable of causing death or distress in cattle.  (Fuller 385).      The seeds of C. arvensis are poisonous.  Eating a quantity of the seeds causes nausea, digestive upset, hallucinations, blurred vision, mental confusion, lack of coordination, stupor and coma.  The nervous system may show great contrast; even in the same individual and at the same instance, they can change rapidly.  (James 49).      A fairly large genus of wide distribution.  (Munz, Flora So. Calif. 375).

Text Ref:  Collins 181; Hickman, Ed. 521; Munz, Calif. Flora 375; Robbins et al. 342; Roberts 20.

Photo Ref:  June 7 83 # 14,15; July 1 83 # 5.

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

First Found:  June 1983.

Computer Ref:  Plant Data 231.

Have plant specimen.

Last edit 3/4/05.  

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