198 3 THE AUSTRALIAN NATURALIST. 
Veronca plebeia, Schrophularineae. 
Ruellia australis, Acanthaceae. 
Prostanthera denticulata, Labiateae. 
Muhlenbeckia gracitlima, Polygonaciae. 
Pimelia linifolia, Thymeleae. 
Beyeria viscosa, Euphorbiaceae. 
Croton verreauait, Euphorbiaceae. 
Dipodium punctatum, Orchideae. 
Microtis porrifolia, Orchideae 
Liliaceae. 
Wurmbea dioica, 5 
“e4 | 
THE SECRETION OF NECTAR BY EXTRA-FLORAL 
GLANDS IN THE GENUS ACACIA (WATTLES). 
(By W. M. Carne.) 
Though the real explanation of nectar producing glands. 
in plants may not be quite understood, it is certain that, 
though in many cases the secretion is intimately connected. 
with fertilisation by insects, such a use is secondary, and is 
not-the original cause. .§ 
The following observations were made of the extra-floral 
nectaries of Acacia to see whether they secreted, and if so, 
whether they played any part in the fertilisation of the flow- 
ers. 
Extra floral glands are common in the genus and occur on: 
the phyllodes and leaf stalks, or at the points of attachment 
of the pinnae, or even on floral peduncles either flower-bear- 
ing or reduced simply to a gland-bearing organ. » 
It will be noticed that there appears to be no rule in re- 
gard to nectar-secretions and flowering. Nectar is produced 
in the glands of the younger leaves of strongly growing plants. 
The secretion is probably determined largely by seasonal con- 
ditions. 
In Acacia discolor, nectar is copiously yielded by large 
glands on aborted flower-stalks. So close are the flowers that 
the bees which visit the glands freely may at times cause fer- 
tilisation. It is hard to see any such use where the glands 
and flowers are widely separated. : 
