ALIGHTING-PLACES IN FLOWERS 



99 



Sprengel described such forms as 'false nectar flowers.' The observations of 

 Charles Darwin and Herm. Miiller have proved that the visitors bore into the juicy 

 cellular tissue of our species of Orchis, and thus procure nourishment. Miiller has 

 also shown that very probably some visitors of Cytisus Laburnum and Erythraea 

 Centaurium bore for sap that is enclosed in the flowers, and it is not improbable that 

 the more industrious bees and Lepidoptera may pierce many other flowers for the 

 same purpose, using the tip of their proboscis as a boring-instrument. It is a fact 

 that Lepidoptera, which are only able to feed on fluids, not infrequently remain 

 for a considerable time on pollen flowers with the proboscis sunk in their bases, 

 e.g. Helianthemum alpinum (Herm. Miiller, ' Alpenblumen,' p. 162), so that we are 

 justified in assuming that these insects bore for sugary juice. In other plants, 

 e. g. in species of Pinguicula, instead of nectar the visitors find little knobs distended 

 with sap, that seem to offer them nourishment. In species of Verbascum, Hyperi- 

 cum, and Lysimachia, club-shaped glandular hairs on the filaments, or similar hairs 

 on the inner side of the petals, appear to supply material for moistening the pollen, 

 and causing it to stick. Such peculiarities of particular flowers will be dealt with at 

 length in the second volume of this work. 



Besides pollen, nectar, and juices obtained by boring or gnawing, many insects 

 take from the flowers they visit other parts not originally destined for this purpose. 

 Numerous flower-visiting beetles (Chrysomelidae, Lamellicornia, Curculionidae) 

 devour stamens, petals, or other floral parts, and thus inflict almost unmixed injury, 

 since they only exceptionally confer the benefit of cross-pollination. In individual 



Fig. 16. Alighiing-Pliicts. (l) Pedicularis verlicilla/a, L.; the lower lip serves as an alighting 

 place. (2) Hippocrepis comosa, L. ; the wings and keel are alighting-places. (3) Aconitum Napellus, L. ; 

 the two lower sepals serve as platforms. 



cases, however, the damage may be compensated for by the benefit (e. g. in Crambe 

 maritima, see p. 102), or, the destroyers of certain floral parts may even be absolutely 

 indispensable for the pollination of the plant (cf Yucca and Ficus, pp. 102-4). 



The visits of insects effecting the pollination of flowers may be facilitated by the 

 provision of a seat, which is as comfortable as possible. Such small flowers as are 

 united into conspicuous societies have suitable resting-places in their crowded 

 inflorescences. The capitula of the Compositae, the umbels of the Umbelliferae, 

 the catkins of willows, and the like, are at the same time both chair and spread table. 

 Larger flowers frequently possess special alighting-places, e. g. the Leguminosae in 



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