68 MORPHOLOGY. 
however, also appearing as appendages of the perigon (Ranuncu- 
lus), or as metamorphosed parts of the perigon itself (spur), or 
even as appendages of the stamens (Crucifere, Lauracee). 
The form of the nectaries is also exceedingly variable. In the 
case of Huphorbia Cyparissias, for example, they have the 
shape of a half-moon. 
The flower-stalk or peduncle bears the flower (los) which, in 
consequence of the bright colors of its corolla, attracts the insects 
for fertilization. This is the physiological significance of the 
color and fragance of the flower. Insects are especially attracted 
by the labellwm of flowers of the Orchidacex (the posterior leaf 
of the inner perigon circle) and of the Zingiberacese (the meta- 
morphosed lowest stamen of the outer staminal circle), as also 
by the vexillum of flowers of the Papilionaces (the uppermost 
petal). 
When in a flower both the calyx and corolla are present, 
the leaves of the calyx or the sepals (sepala') are mostly green, 
while the leaves of the corolla, or the petals ( petala*), are of an- 
other color. When both cannot be distinguished, or one of them 
is wanting, the floral envelopes are spoken of as a perigon.§ 
When the individual leaves are united or coalescent, the floral en- 
velopes are termed sympetalous,* gamopetalous* (synsepalous, 
gamosepalous); when they are separate, choripetalous° (chori- 
sepalous), or also spoken of in general as gamophyllous and 
choriphyllous. 
According to the arrangement of the floral leaves in the bud, 
there are distinguished the following forms of wstivation : 
Valvate (Malva, Vitis), Fig. 4a; 
Imbricate (Geranium, Veronica, Rosa), Fig. 4b and 6; 
Convolute (Gentiana, Phlox), Fig. 5; 
Plicate or plaited (Campanula), Fig. 7 ; 
'Separ, divided (?) 
* Tlérador leaf. 
* ITepz around, and yéros ‘brood, seed. 
* Dur together, and zérador leaf. 
’Tauos marriage, and zérador leaf. 
° Xwpil@ to divide (yapis separated), and zérador leaf. 
