167 



a line with i6oth Street, of an apetalous form of Saxifraga Vir- 

 guuensis. In two plants out of a dozen the five petals, in fully 

 half the flowers, had been regularly converted into stamens, 

 making the total number fifteen, five single ones alternating with 

 five anteposed pairs. Visiting the station again this spring, (May 

 6th), I found three more of these apetalous saxifragas, agreeing 

 exactly with those previously collected, although none of them 

 . was so perfectly developed as the best of last year's specimens. 



Hardly more than on^ or two oi the flowers displayed the full 

 fifteen stamens, and many had fewer than ten, though even in 

 these the characteristic anteposed pairs occasionally occurred. 

 In the three plants in question, there were no indications at all 

 of norrr^al petals ; in a fourth, however, with the taller stem and 

 looser flower cluster of the specific type, a great many of them 

 Avere white and obviously petaloid, and y^t much reduced in size 

 and in some cases with partially formed anther cells. This tran- 

 sition state is very common in many plants where stamens are 

 turning into petals. The interest in this case arose from the fact 

 that here the much rarer change of petals into stamens was actu- 

 ally and visibly taking place. The discovery of these additional 

 specimens strengthens my opinion that a saxifrage of this apeta- 

 lous fifteen-stamened form, occurring by chance, matured seeds 

 from which the plants collected in two successive years were pro- 

 duced. To my mind we have here a very curious and interest- 

 ing, though as yet scarcely successful, attempt on the part of 

 nature to estabfish a good variety by perpetuating what must 

 nave been originally a mere teratologicalVariation. 



E. E. Sterns. 



Rules for the Botanical Exchange Club. 



It having been decided to organize the American Botanical 



^ i^^uii v^i^^iui^\j \,\j wig 



Exchange in connection with the National Herbarium in the De- 

 partment of Agriculture, the Botanist of the Department will act 

 as Director of the Exchange, and the following rules will be fol- 

 lowed in its managemet, until further notice. 



I- Persons desiring specimens are required to contribute a 

 number regarded as equivalent in value to those called fon The 

 specimens wanted in return may be selected when the others are 

 sent or at any time afterw^ard. 



