NATURE NOTES, 117 
LEAF METAMORPHOSES. 
THE leaf performs so many good offices for the plant that 
it may be regarded as a sort of Man-Friday or Caliban. 
Besides throwing out myriad hands to catch stray particles 
of atmospheric food for its master, besides being a living 
crucible for transmuting raw material into chlorophyll, 
parenchyma, gluten, etc., it is called upon to undergo many 
transformations. No sooner has it arrived at the stage of 
being a leaf than some inward force whispers that other and 
higher functions await it. So the leaf toils painfully up the 
spiral staircase of the stalk. Look at a stem, and try in 
fancy to drop out the internodes; or imagine the stem 
pressed together from top to bottom, and you will find the 
leaves winding round like the steps of a corkscrew stair. 
Follow the leaves of the common double peony up the 
stem, and try to put your finger on the leaf where it ceases 
to be a leaf and becomes a bract, forming part of the calyx. 
Then another stage comes: the bracts are suffused here and 
there with a glow of colour; the green is fading before the 
flush of the flower. Still following the magic circling of the 
leaf, the flush overrides the green, and the petal lies in our 
hand glowing like a sea-shell. The tide of the flower-colour 
breaking over the topmost stems and leaves is well seen in 
many plants. In the common wood-hyacinth I have seen 
it showing sea-blue through leaf-tips and stems; or you may 
see it in the milkwort, where the leaves, as they reach the 
flower, catch its first radiance. But the petal, changed 
though it be, still bears all the true leaf characteristics 
of stomata, parenchyma, veins, and cuticle. Then, once 
again, the plant draws -upon the leaf-substance to form the 
carpels of the ovary. A leaf folded lengthwise is the first 
rough sketch at a shelter for the precious ovules. 
If you examine a row of garden peas, you are not unlikely 
to come across an abortive pod, a thickened, folded leaf 
which, for some reason or other, has not been able to grow 
into a perfect seed-vessel. It will, probably, show little 
processes along its edge where the ovules would have grown 
had something not gone amiss. 
