BY AGNES A. BREWSTER. 757 



visit tiie Hower-clusters of D. fascicularis. The visitations of tiiese 

 birds, then, make the cross-pollination of Darwinia very simple, 

 for the pollen-masses held by the substigmatie hairs, and carried 

 up by the elongating style, are carried off by the bird as its head 

 brushes the flowers. At the same time, pollen is placed on the 

 stigmas of mature flowers, either of the same cluster or of adja- 

 cent ones. The closing of the corolla-lobes is a means of keeping- 

 out small creeping insects which would be useless to the flowers, 

 because they might steal the nectar, without touching the stigma or 

 the pollen below it. 



These plants, when once established in a district, are plentiful, 

 and must fruit freely. 



I examined dozens of mature flower-clusters to see if there was 

 any sign of the stigmas being brought down to meet the remains 

 of the pollen-masses on the substigmatie hairs, and so causing self- 

 pollination, should cross-pollination have failed to take place; but 

 there was not one style which had so bent in order to bring the 

 stigma in contact with the hairs. 



I also noticed that it was only in comparatively few flower-clus- 

 ters that there was an excessive supply of nectar so as to run over 

 the edges of the flowers of such clusters; and I wondered whether, 

 in these inflorescences, visitors had not come, and the excessive 

 nectar was given off to make a special attraction (for such flowers 

 glitter in the sun), or whether it was the result of the accumulation 

 of unused nectar. 



The pollen-grains of D. fascicularis are typical of the Natural 

 Order Myrtacese, being formed of two curved, solid triangles, base 

 to base, with clear triangular outlines, when viewed under the 

 microscope. At each of the truncate angles of the pollen-grain, 

 there is a button-like, transparent protuberance, which marks the 

 spot where the pollen-tube may issue.. I put some of the grains in 

 a weak sugar-solution over night, and tubes had developed in the 

 morning. 



I submerged flowers in water, and found, after two days, dozens 

 of pollen-grains with well-advanced germ-tubes developed. One 

 interesting example was seen of a mass of pollen on the substig- 



