COROLLA. 
m 
animal substances. Many flowers exhale sw eet odors ; but, however odors may 
differ in the sensations which tliey produce, it is certain that powerful ones have a 
stupefying, narcotic effect upon the nerves, and that it is dangerous to respire for 
any great length of time even the most agreeable of them in a concentrated state. 
b. One important office of the corolla, is to secure those delicate and important 
organs which it incloses, the stamens and pistils, from all external injury, and to 
ftivor their development. After the germ is fertilized by the influence of the pol- 
len, the corolla fades away, and either falls off or remains withered upon the stalk; 
the juices which nouiished it then go to the ovary, to assist in its growth, and ena- 
ble it to become a perfect fruit. Another use of the corolla seems to be, to furnish 
a resting-place for insects in search of honey. The corolla is supposed by Darwin 
to answer the same purpose to the stamen and pistils, as the lungs in the animal 
system ; each petal being furnished with an artery which conveys the vegetable 
blood to its extremities, exposing it to the light and air under a delicate moist 
membrane ; this vegetable blood, according to his theory, is then collected and 
returned in correspondent veins, for the sustenance of the anthers and stigmas, and 
for the purpose of secreting honey. After all our inquiries into the uses of the 
corolla, we are obliged to acknowledge that it appears less important in the econ- 
omy of vegetation, than many less showy organs. It seems chiefly designed to 
beautify and enliven creation by the variety and elegance of its forms, the bril- 
liancy of its coloring, and the sweetness of its perfume. 
Y5. In many flowers there is an appendage, formerly called 
tlie nectary (from necta/r^ honey)^ which secretes a peculiar fluid, 
the honey of the plant. Linnaeus considered the nectary as a 
separate organ from the corolla ; and every part of the flower 
\;\^hich was neither stamen, pistil, calyx, nor corolla, he called a 
nectary ; but what he called nectaries are at present regarded 
as modifications of some part of the flower ; in some cases a 
mere prolongation of the petals, and in others an inner row ol 
j)etals or modified stamens adhering to the corolla. With this 
explanation, we shall use the term nectary as it has been ap- 
plied by preceding writers. 
a. The term disk is now applied to w^hatever appendage ap- 
pears betv/een the stamen and pistils, formerly called nectaries ; 
the disk is often formed from the degeneration and transforma- 
tion of stamens, presenting the appearance of scales, glands, 
hairs, &c. Its common form is that of a rim or scale^ either 
surrounding the base or appearing at the tip of the ovary ; it 
sometimes consists of glands or abortive stamens, alternating 
with the stamens, sometimes at their base, showing a whorl oi 
abortive stamens. 
Sometimes the disk or nectary is a mere cavity, or gland, as in the lily. The 
crown-imperial exhibits in the claw of each of its petals a nectary of this kind 
each one being filled with a sweet liquid, the secretion of the flower. The six 
nectariferous glands at the base of the corolla are represented at Fig, 82. The 
petals are supposed to be cut to show the base of the flower. The analogy of 
oetals with stamens is argued from the existence of these glands or cavities, the 
nuid contained in them being found to be of the same nature as that which is 
elaborated into pollen. 
lu the ranunculus the secreting organ ie a production of the corolla in the form 
Dangerous if respired for a long time— 6. Offices of the corolla — Darwin's theory with respeo t!w 
jorolid. — 75. Nectary — Its use — a. Nectaries not cousidereU as a special organ — a. Diak. 
