ABSTRACTS. 



1179 



Plane-leaf Scorch. By H. Klebahn (Zeit. f. Pflanz. xii. p. 258 ; 

 1902). — Preliminary note on discovery of a perithecial ascus-stage on 

 fallen leaves of Oriental Plane, which in summer bore the conidial form 

 (Glee ospor iu m nervisequum). — W. G. S. 



Plant-growth, Effect of Acetylene Gas-light on. By F. W. 



Rane (U.S.A. Agr. Exp. Stn. Neio Hampshire, Tech. Bull. No. 4; 

 October 1902) — This is a description with photos of experiments on 

 several plants, under a cluster of 8 burners and a 20-inch reflector. One 

 half of the bed was curtained off during the night for comparison. On 

 January 1 the lights were started and run each night till February 15, 

 1901. On January 8 the plants, especially Lettuce, began to show an 

 increase of growth. By January 16 there was a marked difference in 

 Lettuce, Parsley, and Beans, but not so much with other plants. The 

 following were the conclusions ultimately arrived at : 



1. That acetylene gas-light has a marked effect upon greenhouse 

 plants. 



2. That no injurious effects occurred. 



3. It stimulates and appears to be beneficial to foliage crops. The 

 Lettuce was more erect and weighed more. 



4. Most plants were taller. 



5. It is doubtful whether this light can be used economically ; while 

 its effects are marked in winter, little difference was seen in other seasons. 



6. There are many points about the acetylene gas-light that make it 

 desirable for lighting greenhouses. It is not expensive, is easily piped, 

 and comparatively simple to run. — G. H. 



Platyosprion platycarpum. By G. Nicholson (Garcl. Chron. 

 No. 824, p. 259; Oct. 11, 1902).— This handsome tree, though collected 

 in Japan on Fusiyama in 1864, has only just found its way into cultiva- 

 tion. It is probably rare in its native country. It somewhat resembles the 

 well-known Sophora japonica, but it differs from that plant in many 

 distinct particulars. — G. S. S. 



Platytheca galioides. By W. T. {Garcl. Mag. No. 2544, p. 496 ; 

 2/8/1902). — Mention is made of this descriptive and cultural note on this 

 beautiful Australian greenhouse shrub in order to draw attention to the 

 fact that it is a new name for a well-known plant known under the names 

 of Tremanclra verticillata and Tetratheca verticillata. — W. G. 



Polemoniums. By G. (Gard. Mag. No 2544, p. 494 ; 2/8/1902).— 

 A good account of the various species and varieties of this genus (Jacob's 

 Ladder), with practical cultural notes, for, though the species are as a rule 

 easily grown plants, some, such as P. confertum, are among the most 

 capricious plants in the rock garden. A good illustration is given of 

 P. humile. — W. G. 



Pollen. By C. Druery (Joum. Hort. Dec. 11, 1902, p. 521).— Inter- 

 esting notes on the nature and form of the pollen grains of different 

 plants.— C. W. D. 



