^92 Cooke and Schively on Observations on the 



from experience in gathering the tubercles. Thus the seed 

 hes loose in the soil, awaiting the favorable contact of the 

 beech-root. Now such variation in the size and time of 

 appearance of these plants is shown, that granted the seed's 

 ability to retain vitality, the germination may occur when 

 the new roots of beech reach their vicinity, even though 

 this should be early in the next season. No other hypothesis 

 will explain the constant succession of young plants well into 

 the summer. 



Several attempts to study the germination have been 

 made, but as yet these have proved unsuccessful. Many 

 factors combine to render this a difficult problem. The 

 extreme minuteness of the seeds, the small proportion of 

 these which develop into plants, the apparent necessity for 

 chemotactic contact with the beech-root, and possibly some 

 soil peculiarity, all combine to make successful study some- 

 what troublesome. 



The Development of the Young Plant. 



A young tuber about one-sixteenth inch in diameter has 

 an irregularly elliptical outline, being longest in a vertical 

 direction. It has a one-celled epidermis of cubical, nucle- 

 ated cells, with slightly thickened walls. The cortex is of 

 large thin-walled cells, well filled already with starch. A 

 few bundle-masses stream irregularly through the cortex, 

 in every direction, near the base of the tuber. Several of 

 the larger bundle-masses lie about in the centre of the tuber. 

 These bundles are of densely stained embryonic cells, with 

 scarcely any thickening developed. They are still in a quite 

 primitive, undifferentiated state. 



No roots have emerged as yet. One only may be seen 

 forming within the tuber. But the group of embryonic 

 cells is as yet in a relatively deep portion of the cortex. 

 There is in the whole tuber only this single root-trace as yet. 



Such a plant is one that establishes a lateral connection 



