362 CuuRCH: THE BULB IN COOPERIA DRUMMONDII 
Fic. 12. Detached young ‘‘offset’’ with two scales already formed; it arises 
Sais between the mature scales as a ae on. 
. 13. Young “‘offset’’ h has pierced the outermost scale of the bulb; 
root contraction in old bulb not eas, leaves and roots diagrammtaic; scale = 
PLATE 16 
Fic. 14. Fifty-four- to sixty-one-day-old seedling. The cotyledon has become 
shriveled up and dead. As the first leaf is surrounded by the basal sheath of the 
cotyledon, so this second leaf sheath is surrounded by the basal sheath of the first 
leaf, in respect to which it is distichously placed; see Fig. 9; scale = 1 cm 
Fic. 15. Longitudinal section of thirty-one-day-old bulb; see Fic. 11; scale 
= 0.1 mm. 
Fic. 16. Longitudinal section (not central) of thirty-one-day-old bulb; 63 and 
13 are the points at which the primordia of the third leaf are forming; otherwise the 
symbols are as in preceding drawings; scale = 0.1 mm. 
Fic 17. Longitudinal section (not central) of thirty-seven-day-old bulb; 1/4 is 
the fourth leaf, not a central section; the puckered or wrinkled condition of the 
primary root is due to contraction, a normal phenomenon; the outlay of root tissue 
has a narrow slice marked off into three sections—r, 2, and 3—for details of which 
see Fic. 19; scale = 0.1 m 
Fic. 18. Longitudinal section through thirty-seven-day-old seedling with a 
young root showing a well-differentiated root cap and primary tissues (dermatogen, 
periblem and pleurome); sca 
G. Showing under high-power magnification the root tissues laid off 
between the numbers 1-3 in Fic. 17; for further explanation consult text; scale 
