Flowers 
The sepals are sometimes, surely, only protective 
bracts which have been further modified. Either sepals 
or petals and sometimes both of them become abortive. 
Occasionally petals become stamens, which may mean 
that in those cases they were at first modified stamens. 
In a sense one might say that flowering is the end 
towards which every effort of the plant is directed. 
Quite a number of the Monocotyledons die as soon as 
they have flowered. Young trees which are unhealthy 
and miserable-looking often produce great quantities of 
flowers and fruits and at a very precocious age, long 
before their normal and vigorous contemporaries show 
the slightest desire to flower. One might suppose that 
such miserable seven- or eight-year-old trees had a 
foreboding of death and wished to do what they could 
to perpetuate the species. One sees the same hurried 
flowering also when cut off leaves of Torenia are in- 
duced to take root. The ugly little stems so formed 
flower when only an inch or two in height. 
But such facts do not necessarily bear out any such 
explanation. 
In a flower, the life that is going on differs in many 
ways from the ordinary proceedings in other parts of 
a plant’s body. There is a very active formation and 
storing up of rich proteids, sugars, hard stony substances, 
colouring materials, strong perfumes and the like, which 
. may not be required anywhere else except in the flowers. 
So it is not surprising to find that the temperature in 
an opening flower is often distinctly higher than that 
of the surrounding air. So also the respiration in 
lobed leaflet carrying a female sporangium. _ Bower thinks that all green leaves 
were at one time spore-leaves and only intended to bear a sporangium, 
Gradually more and more of their cells became sterile and ceased to produce 
spores, but this refers to the time when the plants were primitive ferns and 
long before flowers appeared. 
I1o 
