1919] HORTICULTURE. 833 



The inoculutiou of soil in pots witli a ricli nodule infusion increased consid- 

 erably the number of nodules produced per plant over tliat produced by inocu- 

 lated seed alone. 



While it is not recommended that inoculated seeds be storetl for long periods 

 of time before planting, a delay of several days or a month is believed to do no 

 harm. There appeared to be little difference in the resistance to desiccation 

 whether nodule infusion, commerciiil cultures, or soil is employed as the in- 

 fecting agent. 



Farm weeds of North Carolina and methods for their control, II, J. L. Bxtr- 

 GESS and C. H. Waldron {Bui. N. C. Dept. Agr., J,0 {1919), No. 8, pp. 53, figs. 

 2-')). — In a further contribution to the subject (E. S. R., 38, p. 141), the authors 

 describe and illustrate 25 important weeds found in the State, together with 

 information relative to their eradication and control. 



HORTICULTURE. 



The aerial fertilization of plants with, carbon dioxid, ]\I. B. Cummings and 

 C. H. JoxXES (Vermont /S7a. Jliil. 211 (WIS), pp. 3-5G. plfi. 4)-— A detailed account 

 is given of experiments conducted to determine the general behavior of green- 

 house plants aerially supplied with carbon dioxid iu excess of that normally 

 contained in the air. The trials were begun in 1909 and continued for seven 

 years. Widely dissimilar types of plants were chosen, beans and peas repre- 

 senting the legumes ; radishes and potatoes the root and tuber cropsj lettuce, 

 Swiss chard, and endive the foliage plants of the salad class; the strawberry 

 of the fruit crops ; and nasturtium and cyclamen of the flowering plants. The 

 work for the earlier years consisted in learning methods of procedure. The 

 data presented are based upon results secured from 1911 on. It was found 

 impossible to supply an .excess of carbon dioxid in closed receptacles which did 

 not subject the plants to abnormal conditions of humidity and ventilation. 

 Hence open cases were employed in all of the trials. The carbon dioxid was 

 generated continuously, liberated slowly, and allowed to bathe the plants by 

 dispersion. The results of the several trials are presented in tabular form 

 and discussed. Earlier investigations along similar lines are briefly cited. 



The early effect of an extra carbon dioxid dosage on beans was to stimulate 

 the growth of the seedlings, thus producing larger plants. The later effect was 

 to enhance the production of pods and beans and slightly to change the chemical 

 composition of the plant by proportionally increasing the carbohydrate storage. 

 Peas were similarly benefited. Roots responded less favorably than did most 

 of the plants used in these trials. The results, however, were positive in all 

 instances. Weight increments were distributed in roots and stems, but 

 chiefly the former were affected. Treated roots and plants grew faster than 

 the untreated ones, became edible sooner, and exhibited larger carbohydrate 

 and smaller protein contents. 



Potatoes, as a rule, grew more leaflets and more, heavier, and l>etter tubers 

 when dosed with carbon dioxid. Tuber formation did not begin earlier, but 

 proceeded faster when once started. In one-fifth of the trials the untreated 

 plants weighed less than did the treated ones. Swiss chard and endive re- 

 sponded to gas treatment by producing larger and heavier foliage and by 

 maturing earlier. The trials with lettuce were less conclusive, but in a 

 majority of Instances the treatment seemed beneficial. The foliage of straw- 

 berry plants vcas more abundant and heavier, and the total weight and num- 

 ber of fruits far in excess of the production of untreated plants. Cyclamens 

 either yielded more flowers or showed gains in weight of corms when extra 

 carbon dioxid was furnished. Treated nasturtiums gained consistently when 



