450 THE AMERICAN NATURALIST. [Vov. XXXIII. 
tions of insects, The leaves and acorns of our common oaks, The 
life history of the toad (with a unique tail-piece), and The birds and 
I, are the titles of some of the leaflets. 7 
Elementary Science Bulletins of the Michigan Experiment Sta- 
tion, of which six have thus far been issued, dealing with Beans 
and peas before and after sprouting, Wheat and buckwheat before 
and after sprouting, Timothy and red clover before and after sprout- 
. ing, Leaves of clovers at different times of day, Branches of sugar 
maple and beech as seen in winter, and Potatoes, rutabagas, and 
onions, are comparable with the Zzeacher’s Leaflets of the Cornell 
_ Station. All of the series yet issued are by Professor Beal. e 
Water-Lenticels. — In a recent number of the Forstlich Naturwis- 
senschaftliche Zeitschrift, Tubeuf discusses the formation of water- 
lenticels and their significance. After a brief statement of some 
previous views as to the occurrence and function of ærenchyma 
tissue, he puts the following questions : 
1. Is the development of water-lenticels due to the irritant influ- 
ence of the liquid water surrounding the stem, and is their develop- 
ment above the water due to a transmitted stimulus? 
2. Is their development due to lack of oxygen? 
_ 3. Is their development an ecological adaptation of woody plants 
living in moist localities, or is their occurrence a general one? 
He concludes that their occurrence is not a peculiarity of plants 
in moist soils, but is a general attribute of woody stems. Further- 
more, the lenticels formed whenever there was moisture; in other 
words, /iguid water was not necessary, hence there is no such thing 
as transmitted stimulus. 
He comes to no definite conclusion as to the relation between lack 
of oxygen and profuse formation of water-lenticels, but is inclined to 
regard the water as the potent factor. A number of figures accom- 
pany the paper, showing water-lenticels of Sambucus, Ulmus, and 
Caragana. It may be mentioned that water-lenticels and ærenchyma 
on branches of Sambucus and other woody plants were described 
and figured by von Schrenk in Zrans. Am. Micr. Soc., Vol. VII (1896), 
p. 98, Pls, I-III. T. 
Root-Tubercles of Alder. — The tubercles found on the roots of 
the alder and genera of the Eleagnacez were attributed by their dis- 
coverer, Woronin, to a fungus which he called Schinzia alni, and which 
