ae 
partiv.} . GENERAL RETROSPECT. 517 
devour the anthers, carpels, or petals of honeyless and honey- 
yielding flowers indifferently." 
Since honeyless flowers are usually soon abandoned by honey- 
seeking insects without being secured from the visits of destructive 
beetles and without being visited the more diligently by pollen- 
collecting insects, such flowers are cateris paribus at a disad- 
vantage compared with those which contain honey. But in most 
cases this disadvantage is in some way counteracted, generally by 
superabundant production of pollen, in many cases also (Papaver, 
Hypericum perforatum) by extreme conspicuousness ; in this latter 
case, even such insects as find little or nothing of use to them, 
yet search through a few flowers and effect cross-pollination to 
a certain extent. But when in honeyless flowers with exposed 
anthers, the production of pollen and the conspicuousness of the 
flowers remain low, as in Solanum, Hypericum hirsutum, H. quad- 
rangulum, H. humifusum, Agrimonia Eupatoria, Anagallis, insect- 
visits are so rare that the species is only preserved by the regular 
occurrence of self-fertilisation. 
Honeyless flowers with concealed anthers will be more 
readily understood when we have studied the effects of deeply 
placed honey. 
The concealment of the honey in a nectary protected by other 
parts of the flower, processes, hairs, ete., is of advantage to the 
plant in two ways: it protects the honey from rain, and it permits 
a larger supply to be accumulated, thus attracting visitors in an 
increased degree. With these advantages are connected two 
disadvantages: the honey is the less easily discovered the more 
it is protected from rain, so that a great host of the less acute 
visitors are excluded from it; and the more intelligent visitors, 
which are able to detect it, cannot obtain it so quickly as if 
it were more exposed, so that the work of fertilisation goes on 
more slowly. Both of these disadvantages can be diminished by 
special contrivances, and even turned into advantages. For ex- 
clusion of the multitude of less intelligent, short-lipped visitors is 
1 The honeyless flowers with freely exposed anthers which I have most carefully 
examined are Clematis recta, Thalictrum aquilegifolium, T. flavum, Anemone 
nemorosa, Papaver Rheas, Chelidonium majus, Helianthemum vulgare, Hypericum 
perforatum, Agrimonia Eupatoria, Spirea Ulmaria, S. Filipendula, and S. Aruncus. 
On these twelve plants I noted 145 distinct insect-visitors. I saw 40 bees collecting 
pollen, 6 feeding on pollen, and 4 boring the tissues of the flower for sap ; 2 other 
Hymenoptera feeding on pollen, 2 intent on capturing flies, and 4 apparently seeking 
in yain for honey ; 57 Syrphide feeding on pollen ; 5 Muscide feeding on pollen ; 
2 Bombylii boring for sap ; 3 Diptera apparently seeking vainly for honey ; 18 beetles 
devouring pollen and anthers, and sometimes carpels and petals; 2 Lepidoptera 
seeking in vain for honey. 
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