of Westralian Plants . 227 
that the flies obtain the juice by squeezing or sucking it through the 
cell-walls without injuring them. 
A genus of small terrestrial Orchids, Pterostylis , has received con¬ 
siderable attention from me. As I have given a fairly full account of my 
observations in ‘Annals of Botany’, vol. xxiii, p. 265, the briefest mention 
is sufficient here. T. F. Cheeseman in ‘ Trans. N. Z. Inst.’, vol. v, was, 
I believe, the first to give an account of the mechanism of the flower. 
R. D. Fitzgerald also describes it in his great work, ‘ Australian Orchids ’. 
My own observations and conclusions were, however, made and reached 
independently before having read the account given by either of those 
authors. Further observations and experiments have tended to confirm 
my conclusion that the flowers are pollinated by gnat-like Diptera. 
Cephalotus follicularis , Labill., claims inclusion here on account of its 
intrinsic interest, though my knowledge of its flower biology is far from 
complete. The inflorescence is a narrow panicle of small starry white 
flowers. It is borne upon a remarkably long foot-stalk, which serves to 
elevate it well above the sedges and low shrubs closely surrounding the 
plant. The calyx is a shallow cup with limb divided into six triangular 
lobes. Each of the twelve stamens has a comparatively large gland, 
strongly suggestive of a miniature strawberry, at the back of the anther. 
When the flower opens the stamens are reclined, and their glands form 
two neat rows round the conical pistil, whose style tips are closely folded 
together. Soon a few (2, 3, or 4) of the outer row of stamens unbend and 
their anthers dehisce. The rest come into action on the following day. 
The stamens of the inner row behave similarly on the two succeeding days. 
Then the style tips spread out and the stigmas ripen. The anthers have 
usually lost all their ‘ moist ’ or waxy pollen before the styles diverge. 
The flowers exhale a faint perfume reminiscent of fine honey. There is 
no free nectar, but the inner surface of the calyx tube is studded with 
glistening papillae containing sugary sap. I have seen the flowers visited 
by hymenopts and by Diptera. All the visitors seemed equally efficient 
as pollinators. The inflorescence is clearly visible at a distance of 30 yards, 
appearing as a pale grey smudge upon the surrounding verdure. I made 
a rough estimate of its relative visibility by setting up near an inflorescence 
a raceme of small yellow flowers ( Comesperma sp.) and one of scarlet 
Beaufortia , both trimmed to the size of the Cephalotus panicle. The 
last named was quite as visible or conspicuous as the yellow flowers, 
but somewhat less so than the scarlet to my eye. The flowering season 
was not over when I left the locality ; but I found twenty-three panicles 
that had completed their course. Thirty-eight per cent. (261) of their 
flowers (696) had produced follicles. 
Only one anemophilous plant— Opercularia vaginata , Labill. (N. O. 
Rubiaceae)—has received any attention from me. The slightest agitation 
Q 2 
