} 
} 
i r 
pi 
Y 
PART ILI. | THE MECHANISMS OF FLOWERS. 107 
attained through the white colour of the petals, of which the 
flower has two superolateral ones (p), and two anterolateral (p’), 
twice or three times as long as the former. In addition, there 
are petal-like appendages (y, 4, z, 2, 3) to the two lateral and 
_ shorter stamens (a), and others, still larger, to the four longer 
ones (a’, a). The petal-like appendages of these four inner 
_ stamens closely surround the ovary, which is flattened antero- 
posteriorly, sharp-edged on each side, bent slightly forwards, and 
_ divided symmetrically by a partition wall. 
The centre of the base of each petal has a small pouch, and 
_ just above this each staminal protuberance is provided with a 
similar structure; between the two lies a little drop of honey, and 
concealed beneath this is a small, greenish, fleshy honey-gland. 
Both the petals and the longer stamens can be torn away without 
injuring or removing the glands; which seem therefore to belong 
to the base of the flower (receptacle), 
scaanieeestnc aniline 
as » 
nape, — 
Fic. 84—Teesdalia nudicaulis, R. Br. 
1.—Flower, from above. 
2.—Anterior half of flower. 
3.—One of the longer stamens, with a nectary, seen from without. 
4.—One of the two shorter stamens, from without. 
x, y, foliar appendages of filaments ; n, nectary. 
Before the flower opens, the six anthers are all turned towards 
_ the stigma, the four longer ones overtopping it slightly, the others 
standing on a level with it. After the flower has expanded, all 
six stamens twist through a quarter of a revolution; each of the 
_ longer ones turns its anther towards the adjacent shorter one ; 
while each of the two shorter ones turns towards the outside 
_ of the flower. Now the anthers dehisce, and at the same time 
the stigma becomes mature. Insects in reaching the two outer 
_ honey-drops cannot avoid touching with their head or proboscis 
the pollen-covered sides of the two neighbouring anthers; while 
_ those that suck the inner drops only come in contact with the 
: — , 
pollen of a single anther. Owing to the small size of the flower, 
| the insect must touch the stigma at the same time with another 
