x INTRODUCTORY LESSONS. 
a. Lupinus micranthus; 
the first p'umule leaf on 
the left. 6. Lupinus ar- 
boreus, asit appears when 
grown in sand; the root- 
hairs are ladened with 
sand. c, Lupinus densi- 
florus. d. The same, after 
the cotyledons are fully. 
developed, and the plu- 
mule has appeared. 
Lupines or- 
dinarily grow as 
represented in the 
cut at a, but a com- 
mon white-flower- 
ed kind presents at the end of a month’s 
growth the queer appearance shown at d. At 
first the spxreuting seeds appear to be like 
those of other lupines (see Fig. c), but when 
the cotyledens open, they are seen tu be united 
by their broad bases. For two or three weeks the 
cotyledons enlarge; not only becoming broader, but 
thicker; yet we look in vain for a trace of the plu- 
mule. Meanwhile a white pustule has been growing, 
which finally bursts and discloses the partly grown 
leaves of the missing bud, which has all this time 
been hidden in the thick stem below the cotyledons! 
Now, the tough leathery skin of these cotyledons is 
proof against the nightly frosts that prevail at this 
season of the year (December), so they go on pre- 
paring food from the air with which to feed the 
tender plumule, until it also is strong enough to face ¢ 
Jack Frost. If you carefully examine these seeds in various 
stages of their growth, you will learn that the plumule is at 
the bottom of a short tube formed by the united petioles of 
the cotyledons. Sometimes the plumule breaks out through p 
