no MORPHOLOGY 



parts of flowers by special glands called nectArieS. 

 From a fully exposed position, as in most Umbelli- 

 fercU^ to a concealment inside a long corolla-tube, as 

 in taru-lata, Datura, karabi, or in long spurs, as in 

 OrchidacecB and dopati (see fig. 79), there are numer- 

 ous grades of concealment of the nectary; and insect 

 visitors are determined by the position and character 

 of the nectary. In order to render the finding of 

 nectar more easy for insects that have been attracted 

 to the flowers by colour or odour, the petals are often 

 marked with coloured spots or lines or grooves called 

 NECTAR GUIDES, which by their position and direction 

 indicate the place where honey lies concealed. These 

 nectar guides are naturally present in such flowers 

 as are visited by insects during the day. They are 

 wanting in moth-flowers that open during the night, 

 when nectar guides would be of no use. 



Visits of insects are facilitated in many flowers by 

 the provision of a seat or alighting-platform. For 

 instance, the wings and the keel of many Leguminosce, 

 and the lip or labellum of many Labiatce, Scrophu- 

 lariacecB, Acanthacece, Orchidacece, and ScitaminacecB 

 provide such seats. The capitula of the Compositce 

 and the umbels of the Umbelliferce are at the same 

 time "chair and spread table". The alighting-places 

 are always so situated that insects suitable for pollina- 

 tion touch either the anthers or the receptive stigma, 

 while the access of unwelcome insects is prevented by 

 varied contrivances. 



Some flowers offer shelter to the visitors as well 

 as pollen or nectar. During sudden showers nectar- 

 seeking or pollen-collecting guests eagerly take refuge 

 under the overhanging upper lip of Labiatce, or in the 

 campanulate flowers of Convolvulus and Campanula, 

 which also afford shelter to visitors for the night when 



