parti] © THE MECHANISMS OF FLOWERS. 137 
closed. In the second stage, the anthers of the outer and longer 
stamens dehisce ; in the third stage those of the inner and shorter 
stamens, the stigmas still remaining fresh. The flowers are thus 
_ proterogynous with long-lived stigmas. Cross-fertilisation is likely 
to occur not only in the first stage, but also in the later stages, since 
an insect on alighting will probably touch the stigmas before the 
ik stamens. 
i In several cases I have found the outer stamens so much 
bearing tiny shrunken anthers devoid of pollen. Here apparently 
the time between the ripening of the stigmas and that of the 
_ stamens was lengthened; and hence the chance of cross-fertilisation 
increased. In default of insect-visits, self-fertilisation is attained by 
_ the stamens (both outer and inner) bending inwards, still covered 
with pollen, and coming in close contact with the stigmas. 
I found asmall beetle, Olibris affinis, Sturm, one of the Phalacride, 
licking honey on this flower. 
 Arenaria (Mehringia) muscosa, L., is fertilised by Syrphide 
(609). 
Honkeneja (Ammodenia) peploides, Ehrh., is polygamous (Warm- 
ing, 762). 
Sagina nodosa, K. Meyer, is proterandrous (17, 38) and visited 
by Anthrax (609). 
The following additional species are discussed in my <Alpen- 
blumen :—Arenaria biflora, L.; Alsine recurva, Whinb.; A. verna, 
Bartling; Cherleria sedoides, L.; Cerastium adpinunn, BG, 
_ latifolium, L. 
REVIEW OF THE ALSINEZ. 
a he cmap 
_ The foregoing Alsinez are all more or less dichogamous, and are 
mostly proterandrous in various degrees, Arenaria Trinervia being 
_proterogynous. Dichogamy is the more marked the more con- 
' spicuous the flowers, and the more abundant the visits of insects. 
‘Self-fertilisation is totally excluded in none of the above-mentioned 
forms, and is the better insured, the more inconspicuous the flowers 
are, and the more scanty the insect-visits either from that cause or 
on account of the unfavourable time of year. The insect-visitors are 
very various, on account of the accessible position of the honey, but 
_ consist chiefly of flies and the less specialised bees. 
__ Most of the above remarks hold good also for the species which 
