Chess, Bromus secalinus L., and downy brome, Bromus tectorum L., are two of the more common and troublesome weedy grasses in the midwest and western states. Downy bromegrass is widely dispersed in Michigan in pastures, meadows, cultivated fields, and roadsides. Chess occurs frequently in grain fields, particularly in the southern part of the state. These two species have been variously described as annual, winter annual, and either annual or winter annual plants.

Amino triazole (3–amino–1,2,4–triazole) is a chemical which causes chlorosis in many plants. In many cases chlorosis is followed by the death of the plant. It is not known definitely whether the synthesis of chlorophyll is inhibited or whether chlorophyll is destroyed. Generally, only new growth, in which the pigment is being formed, shows chlorosis. This suggests that chlorophyll synthesis is affected. The chlorosis has been shown to be proportional to the amount of amino triazole applied. In order to establish a basis for further work, evidence on the translocation and fate of the chemical in several different plants is presented here.

Numerous workers have reported the presence of growth and germination inhibitors in various plants. In some cases the active principles have been isolated and characterized. It has been further found that some of these inhibitors have a role in the interaction of species. Thus, the compound, 3 acetyl–6–methoxybenzaldehyde, is leached from the leaves of Encelia farinosa and suppresses the establishment of other species in the immediate vicinity of the parent plant.

In 1949, Bruns and Rasmussen initiated studies to determine the length of time certain weed seeds would maintain viability when held in fresh running water. Seeds of white top, Russian knapweed, Canada thistle, morning glory, and poverty weed were placed in Lumite screen bags and submersed at 12- and 48-inch depths in the Prosser Power Canal.

The application of 2,4–dichlorophenoxyacetic acid (2,4–D) in herbicidal concentrations to plants has resulted in a number of correlations with post-treatment physiological and biochemical changes. Whether these changes are of a secondary nature or actually involved in the basic mechanism of herbicidal action cannot always be determined at the present time. One such case is the influence of 2,4–D on the uptake of minerals from the soil. Wolf et al. demonstrated that the content of potassium was considerably lower and calcium was higher in leaves of 2,4–D treated plants than in controls, but when the analyses from the leaves were combined with those of the stems, these differences largely disappeared. They also noted that chlorine and sulfur were higher in treated plants than in controls, while phosphorus was lower in treated plants than in controls. Fang and Butts showed that the amount of phosphorus in the leaves from 2,4–D treated plants was much less than that found in the leaves of control plants, while the amount in either the stem or root from these two groups of plants showed no significant differences. These results have been confirmed by Rebstock et al. who have shown that the total amount of phosphorus in treated plants was lower than that in the control plants, while at the same time the total phosphorus content of the stem tissue from 2,4–D treated plants was higher than that of the non-treated plants. The phosphorus content of the roots was not appreciably changed from that of the non-treated plants. Rhodes et al. noted that treatment with 2–methyl–4–chlorophenoxyacetic acid (MCPA) greatly lowered the potassium content of tomato and rape plants and suggested that the possible mechanism of MCPA action might be by interference with potassium metabolism. However, in a later publication Rhodes reported no effect of MCPA on the uptake of potassium, calcium or magnesium. With the possibility existing that 2,4–D exerts its action through interference with potassium or phosphorus metabolism, the present study was undertaken to examine more closely the influence of 2,4–D on mineral uptake from the soil.

In symptomatological studies with 3–(p-chlorophenyl)–1,1–dimethylurea (monuron2 or CMU) it was found that light intensity had an effect on the type of symptom and on the extent of the injury produced by this chemical. This note is published to direct attention to the influence of light in the herbicidal action of monuron.

Maleic hydrazide (MH) or 1,2–dihydropyridazine–3,6–dione is an organic plant growth regulator which has been found useful in preventing sucker formation in flue-cured tobacco, in preventing sprouting of stored vegetables, and in inhibiting the growth of some weeds and grasses. The compound can be synthesized from hydrazine and maleic acid or by reacting hydrazine hydrate and maleic anhydride. The commercial product, MH–30, is made by reacting MH with diethanolamine (DEA), and contains 58 per cent active ingredient, the remainder being classified as inert ingredients.

The average annual celery production in Florida for the last five years has been 10,080 acres, most of which is grown in organic soils, with a value of 14 million dollars. Florida produces approximately 54 per cent of the celery marketed in the nation during the winter and spring months.

The present paper is supplementary to one previously published which received more comment than had been expected. In the meantime Salisbury's book appeared in which reference was made to the paucity of data on the subject and many records from the previous paper were quoted. Salisbury made statistical and ecological studies of various species in Great Britain.