TEACHERS DEPARTMENT. 
33 
ravines so characteristic of the region of Eisenach in North Ger¬ 
many. It has been noticed by Neger that many of the normal 
plants arose from horizontal runners, which differed from the 
upright shoots in their long internodes and minute leaves, and 
although these runners had not previously been noticed the occur¬ 
rence did not surprise him because it was known that such a con¬ 
dition might readily be produced by extreme dampness or reduced 
light. In winter however all the plants lie parallel to the ground, 
but on account of the steepness of the surface, they hang dowm- 
wards toward the bottom of the ravine. The stems attain a 
very considerable length, as much as 1-2 meters, some of the 
internodes having a length of 6-10 cm. Moreover the ends of 
these hanging shoots, instead of swinging freely, penetrate into 
the mossy turf or loose soil, a unique behavior in such plants. 
The terminal shoots do not however become entirely buried or 
even partly so in all cases, but take on the hibernacular character 
while lying on the sub-stratum. 
This habit is accounted for in part by the fact that these winter 
shoots fail to- respond to the geotropic and phototropic stimuli, 
but do so to the presence of water. Being chiefly hydrotropic 
they enter the substratum. Here the internodes are short, the 
leaves are small and more fleshy than the normal, and when hidden 
from the light, do not become green. Being thus buried they are 
protected from the cold of winter. Taking root they are ready on 
the advent of spring to send out new shoots which are vertical in 
their growth. These curious shoots are then quite comparable 
with the hibernacula of water plants. It is well also to note that 
some if not all of our northern species of Lycopodium behave 
similarly. Thus Lycopodium alopecuroides on the approach of 
the limit of growth, sends the tip of its stem into' the ground or 
moss in which it grows, and this tip, a thickened, starch-supplied 
portion is all which lives till the next season. F. E. L. 
Movement of the Branches in Shrubs and Trees. —Some 
hitherto undescribed facts have recently come to light regarding 
the phenomenon of movement of the branches in shrubs and 
trees.* Observations and measurements made by Professor W. 
* Ganong, W. F., An Undescribed Thermometric Movement of the 
Branches in Shrubs and Trees. Ann. Bof. i 3 . Oct. 1904. 
