292 FOUNDATIONS OF BOTANY ‘s 
an embryo. This grows, remaining for a time attached to the 
macrospore, and at length forms a new spore-plant. 
THE STUDY OF A SCOURING-RUSH (EQUISETUM) 
359. Occurrence. —The common horse-tail, Equisetum arvense, is 
widely distributed in the United States, east, west, north, and south. 
It is very often found on sand hills and along railroad embankments. 
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Fic. 212. — Plant of Lycopodium (LZ. annotinum). 
The fruiting stems appear very early in the spring and are of short 
duration. The sterile vegetative growth follows, becoming well 
grown in June. 
360. Examination of Rootstocks and Roots. — Examine the under- 
‘ground portions of the plant with reference to general size, position, 
color, shape, and position of notches. After studying the stems 
