SOME INTERESTING BOTANICAL FACTS. lxvil 
one pale lilac. All are dimorphous—that is to say 
if a number of specimens are examined, it will 
be found that about half have the stigma at the top 
of the tube and the stamens half-way down; whilst 
the other half have, on the contrary, the stamens at 
the top of the tube and the stigma half-way down. 
This has long been known and distinguished as 
“pin-eyed” and “thrum-eyed.” Although this had 
been noticed for long, it was reserved for the genius 
and perseverance of Charles Darwin to explain the 
significance of this curious phenomenon, and _ its 
importance in the economy of flowers. Now after 
being pointed out, it is quite obvious. When an 
insect thrusts its proboscis down a primrose of the 
long-styled form, it cannot fail to deposit some of 
the pollen carried from, other primroses on the 
stigma. Most flowers require crossing, and we find 
the machinery used of the most unexpected and 
complex description to prevent self-fertilisation and 
induce crossing. In proportion to the brilliance of 
the corolla or the sweetness of the perfume, is the 
need the greater for crossing. Inconspicuous flowers 
are either self-fertilised or only occasionally crossed. 
