610 EXPERIMENT STATION RECORD. 



Summarizing his results, the author states that plants kept at a very 

 low temperature during the night and in the open during the day will 

 be greatly reduced in size, their internodes will be proportionately 

 shortened, their leaves much smaller and thicker, and they will flower 

 much earlier. It is further stated that by an alternation of the tem- 

 perature comparable to that which is produced on higher mountainous 

 regions, it is possible to artificially produce alpine characteristics in 

 plants grown at low elevations. 



Half shade and vegetation, B. 1). Halsted (Proc. Amer. Assoc. 

 Adv. Set., 47(1898), p. 415). — The author reports a number of experiments 

 in shading various truck crops with frames of lath upon supporting 

 stakes; the spaces between the lath equaling their width, so that half 

 the direct rays are intercepted. In general, the shade retarded the 

 germination of Lima beans in the first crop, but the opposite was the 

 case with the second or midsummer planting. All root crops, such as 

 turnips, carrots, and potatoes, had a larger leaf surface in the shade, but 

 the roots were much smaller. The shade improved the growth of salad 

 crops, such as lettuce, spinach, Swiss chard, etc., and celery was 

 improved the most of all. The time of blooming was greatly retarded 

 and the period of fruitfuluess materially prolonged by shading beans, 

 peas, eggplants, tomatoes, cucumbers, aud the like. Leaves grown in 

 the shade are usually of a deeper green color and thinner than those 

 grown in full exposure. 



A study of some wild plants was made in a wood lot and adjoining 

 clearing. The cinnamon fern (Osmunda ciwnamomea), was noted to have 

 graceful, drooping leaves in the wooded land, while in the open they 

 were nearly upright. Measurements of the thickness of the leaflets 

 showed those in the shade to be 0.098 mm., while in the cleared land 

 the thickness was 0.258 mm. Many other differences, such as hairiness, 

 color of stems, etc., were noted between the shaded plants and those 

 grown in the open. 



Influence of carbon dioxid on the form and structure of plants, 

 E.G. Teodoresco (Compt. Rend. Acad. Sci. Paris, 127 (1898), JVo. 6, 

 pp. 335-S38). — The author reports upon a series of experiments in grow- 

 ing Lupinus albus, Phaseolus multifiorus, Pisum sativum, and Faba vul- 

 garis nnder bell jars in an atmosphere containing carbon dioxid greatly 

 in excess of the normal in one case aud little or no carbon dioxid in 

 another. Comparing the development of the plants, those grown in 

 the presence of carbon dioxid had their hypocotyl, or lower internodes, 

 greatly shortened, but the later internodes were elongated to such an 

 extent that the total height of the plant greatly exceeded those grown 

 without carbon dioxid. In addition, the internodes in cross section 

 were much larger and contained a considerably greater number of 

 fibro vascular bundles, the leaves were much thicker, the cells of the 

 palisade parenchyma were considerably elongated, and the intercellular 

 spaces more extensively developed. 



