656 



SCIENCE. 



LN. S. Vol. VIII. No. 202. 



Notes on Some Diseases of Southern Pines. 



Hekmann von Schrenk. 



Of the numerous fungous parasites of the 

 southern pines Trametes pini is one of the 

 most destructive. It attacks older trees, 

 entering through a knot and causing decay 

 of the heartwood up and down the trunk. 

 The mycelium dissolves portions of the 

 wood fibers, at first changing them to cellu- 

 lose. After a time the solution stops, and 

 the wood then appears full of holes with a 

 white lining, the holes separated by lamellae 

 of apparently sound wood. The 'local' 

 action of the mycelium is characteristic 

 of numerous fungi destroying wood. The 

 wood not destroyed seems to be protected 

 against the attacks of the fungus ferment 

 by some substance which infiltrates into 

 the wood cells. In the wood attacked by 

 the mycelium of Trametes jyini, a compound 

 allied to the humus compounds was found, 

 giving the wood a brown color. It is pos- 

 sible that this may be one of a class of pre- 

 ventive substances. 



Another prevalent disease is due to Tra- 

 metes radiciperda, which enter the trees 

 through the roots. The mycelium passes 

 up the trunk, causing decay similar to that 

 of Trametes pini. It was found destroying 

 numerous trees of Pinus palustris and P. 

 ■echinata. 



A remarkable Increase in Size of Leaves of 

 Kalmia angustifolia apparently due to Reduc- 

 tion of Light. Peofessob W. J. Beal. 

 On May 14, 1898, before flowering, some 

 plants with a little soil attached were re- 

 moved from an open place at Grayling, 

 Michigan, where they are common, and 

 transferred to the State Agricultural Col- 

 lege, 130 miles south, where they were 

 planted in muck, kept wet, and screened 

 about 8 feet from the ground with laths and 

 the leaves of trees, which cut off at least 

 one-half of the light during the middle of 

 the day and a larger per cent, morning and 



evening. On July 28th the three branches 

 here exhibited were cut from the plants and 

 pressed till dry. The largest leaf on each 

 branch (measured when dry) is 37 X 17, 45 

 X 16 and 47x15 millimeters, while the 

 largest evergreen leaf (growth of the pre- 

 vious year) is 22x9, 25x6 and 25x6 

 millimeters, i. e., a leaf of this year easily 

 has a surface four times that of a leaf of 

 last year. Similar results were obtained 

 with Kalmia glauca. No control plants 

 were retained. 



Half Shade and Vegetation. De. Byron D. 



Halsted. 



Experiments were made in shading vari- 

 ous truck crops with frames of lath placed 

 upon supporting stakes. The space be- 

 tween the lath equalled the width of the 

 lath, so that one-half of the direct rays 

 were intercepted. The temperature under 

 the frames (monthly averages of daily ob- 

 servations) was lower than in the full sun, 

 as follows: May, 4°; June, 4.2°; July, 6.5°; 

 August, 7.7°; September, 16.6°. In gen- 

 eral the shade retarded germination, no- 

 ticeably of the first crop of lima beans, but 

 the opposite was true for the second, or 

 mid-summer planting. All root crops, such 

 as turnips, carrots, potatoes, had a larger 

 leaf surface in the shade, but the roots were 

 smaller. Shade improved the salad crops, 

 lettuce, spinach and Swiss chard. The 

 crop most improved of all by shade was 

 celery. With seed, or fruit- producing crops, 

 such as beans, peas, egg-plants, tomatoes, 

 cucumbers, the time of blooming was re- 

 tarded and the period of fruitfulness mate- 

 rially prolonged . The foliage is of a deeper 

 green in the shade than in the open. In 

 carrots there is a strong tendency to broaden 

 the dissected portions ; in short, in the 

 various crop plants there is an attempt to 

 increase the size of the blade of the leaf. 

 The behavior of the plants was also dissimi- 

 lar. For example, the exposed bean plants in 



