82 Flowers and their Unbidden Guests. 



delicate fringe round a leaf-like epiblasteme (a so-called 

 para-corolla), as for example in Qentiana nana "Wulf. 

 (Plate II. fig. 72), and Soldanella alpina L. (Plate II. 

 fig. 76), or as simple hairs, i.e. trichomes in the limited 

 sense of the term. As far as function is concerned 

 these morphological distinctions and hair-splittings are 

 utterly irrelevant. What, however, is really of impor- 

 tance, is the manner in which these hair-like structures 

 are grouped inside the flower ; and in this respect we 

 find an extraordinary amount of variety. 



One form of protective appliance which recurs with 

 great frequency, and which manifestly serves to pre- 

 serve the nectar, or much more rarely the pollen, from 

 insects of such small hodily dimensions that in visiting 

 the flowers they would not come necessarily into suc- 

 cessive contact with the stigma and the pollen, is the 

 introduction into the flower of lattice-work and "weels" 

 of hairs.^ These are usually composed of straight 



* These " -weels," whicli are especially frequent in the flowers of 

 Labiatse, as also the internal tangles of tiichomes, which will be 

 dealt with at length later on in this chapter, and of which we 

 have examples in the flowers of various geraniums, have hitherto 

 been usually explained as serving to protect the nectar from rain 

 and dew. But this is certainly a mistaken interpretation. Were 

 it a true one, we ought to find the trichomes dripping with mois- 

 ture after every fall of rain or dew ; which is never the case. Such 

 trichomes are, as a rule, completely covered in by the perianth, so 

 as not to be exposed to rain or dew ; and such flowers as turn their 

 faces upwards when expanded in the sunshine (e.^. most species of 

 geranium) hang them downwards in rainy weather, or when even- 

 ing comes on ; so that the perianth at such times is not like an 

 up-turned funnel, but like a down-turned beU. When leaves form 



