218 Sargent.—Fragments of the Flower Biology 
I estimated the number of stamens at fourteen hundred. Their bases occu¬ 
pied a band round the ovary top mm. wide, while their anther-bearing 
tops spread to a width of about 25 mm. The middle circumference of the 
stamen ring taken over the anthers was 140 mm. The stigma was less than 
a millimetre in diameter ! The area of the pollen -bearing surface was there¬ 
fore over three thousand times the area of the surface adapted for receiving 
pollen. In this estimate I have included the spaces between the anthers; 
but even if that inclusion be disallowed the ratio would still be enormously 
disproportionate. What could be more eloquent of the low degree of 
specialization of this flower ? I have no positive knowledge that birds are 
the chosen agents of pollination in this particular species, but I feel no 
doubt whatever that such is the case. While the above is perhaps an 
extreme case in all species of Eucalyptus the area of the pollen-bearing sur¬ 
face is enormously out of proportion to the area of the stigma, which is 
always minute. This points, I think, to a pollinator of comparatively large 
size. The top of the ovary secretes nectar, often very copiously, so that it 
falls in drops from the flowers. Birds seeking this nectar would certainly 
be liberally dusted with pollen, and could scarcely fail to bring some of 
their pollen-bearing feathers into contact with the stigma. I have many 
times seen small parakeets busy on the flowers of E. redunca , Schau., and 
E. accedens , W. V. Fitz. Once I observed Zosteropsgouldi sipping nectar from 
the flowers of E. loxophleba , Benth. The only species I have observed at all 
closely is E. calophylla , R. Br. Its flowers are freely visited by insects seek¬ 
ing the very copious nectar or pollen. Various honey-eating birds are also 
frequent visitors. The latter appear to be efficient pollinators ; but the in¬ 
sects seem useless : I have never seen one brush against a stigma, though 
I have watched long and carefully. I have found Eucalypts troublesome 
to observe, and I regard my present knowledge of their flower biology as 
very incomplete. Yet what I have so far seen has impressed upon me the 
belief that birds are the chief pollinators of the genus. The small size of 
some of the flowers at first led me to regard them as entomophilous, but 
I am now satisfied that birds could and would take nectar from the smallest, 
and in so doing would almost certainly effect pollination. 
The flowers of Beaufortia sparsa , R. Br., show some degree of special 
structural adaptation to bird pollinators. Sepals and petals are much 
reduced : bud and ovary protection seem their only functions. The stamens, 
bright scarlet in colour, are collected into five slender bundles about an inch 
in length, only their tips being free; the anthers are minute ; and the 
slender style, somewhat longer than the stamens, is tipped by an almost 
microscopic stigma. I often saw small honey-eating birds busily sipping 
nectar from the flowers, during visits to Albany in 1909 and 1910. The 
anthers freely rubbed against cheeks, foreheads, and throats; and I con¬ 
cluded that the birds were very efficient pollinators. This type of floral 
