73 



were not only decidedly more attenuated than those of the con- 

 trol plants and without any indication of curvature, but the stems 

 had not the thickness of those uncovered plants that were grown 

 beside them. While this experiment is not offered as an example 

 of the loss of irritability, since the facts are too meager to warrant 

 such a conclusion, it does show in connection with others that 

 need not be mentioned, that occasional artificial illumination may 

 have a pronounced influence upon the growth of etiolated plants. 

 So it would appear that we must materially alter our conceptions, 

 in many cases, at least, of the term etiolation if we mean by it 

 the development that is possible in total darkness. 

 Columbia University. 



SHORTER NOTES 



A triple Samara in Acer rubrum. — The double samara of 

 the maples is an almost constant feature, although in Acer sac- 

 charinum L. only one samara usually matures, which is doubtless 

 an aid to their better flight. 



The occurrence of a perfect mature triple samara in Acer 

 rubrum L. seems worth recording. (The figure shown herewith is 

 three quarters natural size.) A three- 

 celled, three-lobed ovary is reversionary, 

 and harks back to the days when the an- 

 cestral maples had a three or more celled 

 ovary, and probably two ovules in each 

 cell as they sometimes do now, condi- 

 tions which usually obtain in the order 

 Sapindales. There seems to have been 

 a progressive reduction in these parts 

 throughout the order, which is still 

 going on, the bulk of the Sapindales being inconstant in these 

 features. This reduction effects a great saving in vital energies 

 and material. It may not be amiss to take a glance at what we 

 know about Acer history. 



Acer is essentially a Tertiary and modern genus, although a 

 number of unmistakable samaras have been found in the Raritan 



