28 



aceous than in T. aurantiacum and usually narrower and more 

 acute. The fruit of T. perfoliatum is commonly more numerous 

 and crowded than in T. aurantiacum, mostly 6—8 in each pair of 

 axils, more globose and of a duller yellowish-orange color ; at 

 least, I have never seen it of as deep a flame color as that of T. 

 aurantiacum sometimes becomes. Apparently also the species 

 prefers a more sandy soil in lower, more level woods and thickets. 

 I have been unable to make out much difference in the distri- 

 bution of the two species, although T. perfoliatum is perhaps 

 rather more southern in its range. Specimens seen show a 

 range from New York to Minnesota, Alabama, Kentucky and 

 Kansas. 



A MODIFIED FORM OF RESPIRATION APPARATUS 



By H. M. Richards 



There are many methods of all degrees of complication by 

 which the amount of carbon dioxide evolved by plants may be 

 measured. Many are simply out of the question for a laboratory 

 which is not extensively stocked, requiring as they do a great 

 array of glassware, many air-tight joints, siphons, aspirators or 

 what not, while others are very crude. The writer has found the 

 following simple and easily constructed piece of apparatus very 

 useful for demonstrating in a fairly accurate way and on a some- 

 what large scale the respiration of plants. It is indeed a mod- 

 ification in form but not in principle of a method long used 

 and often figured in many of the text-books. The apparatus 

 referred to consists, as far as the glassware is concerned, of an 

 exceedingly long-necked flask. Such flasks, however, must be 

 specially blown and are consequently hard to obtain and also 

 somewhat expensive. Instead of such a flask, an ordinary Bo- 

 hemian one of I 50 to 200 cc. capacity, with the neck of usual 

 length, is selected. A test-tube, the closed and slightly tapering 

 end of which was just a little too large to slip into the flask's 

 neck, is next taken. By means of a little carborundum or emery- 

 powder it is ground into the flask neck so as to get an air-tight 



