An Illustrated Guide to ARIZONA WEEDS
The University of Arizona Press
CLUSTER DOCK, green dock
CLUSTER DOCK-Rumex conglomeratus Murr.
DESCRIPTION-Slender hairless perennial, reproducing by seed and spreading by vertical rhizomes, which often give rise to several stout spindleshaped taproots. The slender stems are 2 to 5 feet high, simple or branched. The principal leaves, oblong to lanceshaped, are 2 to 8 inches long, on stalks 1/2 to 3 inches long; the upper leaves are much shorter than the lower, and the leaf margins are slightly wavy. The small inconspicuous greenish flowers grow in clusters around the stem from the leaf axils, at intervals of 1/4 to 1 inch. The many-branched flowering part is 1/3 to 1 1/2 feet high, and often constitutes as much as half of the plant in age. The flower, similar to all docks, has 6 floral parts; the outer 3 are small, but the inner 3 enlarge as the fruit and seed mature and surround them. In cluster dock, these inner segments are fiddleshaped, about 1/8 inch long, and each bears a grainlike body on its back. The flower stalks are short and jointed near the base. The achene is dark brown and shining, less than 1/8 inch long; the seed is permanently enclosed within.
DISTRIBUTION-Cluster dock, a native of Europe, is a moisture-loving weed occasionally found along mountain streams at mid-elevations and common in summer crops, particularly after irrigation begins. Found in sorghum, cotton, alfalfa, and the vegetable crops, such as lettuce and melons, also common along ditchbanks and low places where extra water collects. In southern Arizona in Maricopa, Pinal, Graham, and Pima counties, and doubtless other counties, since cluster dock has spread as the agricultural lands in Arizona have increased; 1,000 to about 6,500 feet elevation; flowering March to September or October.
Copyright (c) 1972 The Arizona Board of Regents