124 THE FLOWERING PLANT. 
terminal pores, but, in the undisturbed state, is prevented from 
falling out by the apposition of adjacent pores. Further, a 
slender process or ‘“‘tail”’ stretches from the base of each anther 
towards the corolla. A bee, in trying to thrust its tongue up to 
the nectar, is sure to touch some of these tails, the anther-ring is 
disarranged, and a shower of pollen falls down. 
Barberry possesses irritable stamens. An insect landing on 
the top of the syncarpous pistil (which possesses a stigmatic 
margin) is sure to touch them in trying to get nectar, here ex- 
creted by paired nectaries on the bases of the six petals. The 
stamens then spring suddenly inward, not only dusting it with 
pollen, but often frightening it off to another flower. 
We now come to some flowers in which examination of several 
specimens will show that the same relative position is sometimes 
occupied by the stamens, sometimes by the stigma. 
In the pink, for instance, there is well-marked proterandry, 
and a young flower presents five stamens projecting in the centre. 
Later on these wither, and the two stigmas are protruded in the 
same place. In this case we have successive elongation of organs 
which are rendered parallel by the enclosing claws of the petals. 
A similar end is served by movement of the stamens in the 
blue meadow-geranium. Here the style rises in the centre of the 
flower, and (as this is another case of proterandry) the five lobes 
(stigmatic internally) which terminate it are at first closely 
pressed together. There are five spreading petals and ten spread- 
ing stamens. The outer five of these rise parallel to the style, 
shed their pollen, and retire, their action being followed by the 
five inner stamens. Now the stigmas separate, and can be polli- 
nated. Note here that maturity is reached from without inwards, 
as in a centripetal inflorescence. 
The rosebay willow-herb, which, by the way, presents a case of 
proterandry known since 1790, attains the same end by move- 
ment of the style. The whole flower is epigynous, with four 
spreading sepals, four spreading petals, and eight stamens 
directed downwards. ‘The style, which resembles that of the 
geranium just described, but possesses four lobes only, at first 
curves back between the petals. After the pollen is shed it 
bends forwards, and the four stigmas expand. It is hardly 
necessary to remark that, in the three cases described, different 
flowers are in different stages at the same time, so that the 
expanded stigmas are sure of receiving pollen. 
Similar results to the preceding are attained, without pro- 
terandry, in primrose and purple loosestrife, by the occur- 
rence of bisexual flowers of different kinds (heteromorphism or 
heterostyly). 
