Viscid Peduncles. 5 1 



the peduncles, or on those parts of the axis which are 

 immediately beneath the flowers and over which creep- 

 ing animals must necessarily pass in order to reach 

 them. In Robinia viscosa Vent, the twigs that bear 

 the inflorescences are furnished with five glabrous 

 leaves, free from viscidity; but the twigs themselves, 

 as also the lower part of the peduncles up to the first 

 flower of the inflorescence, are closely beset with dark- 

 brown wart-shaped colleters, and are coated over with 

 an extremely viscid layer secreted by these colleters.^ 



In Epimedium alpinum L. (Plate I. fig. 24) the 

 lower parts of the stem, as also the leaves, are without 

 glandular trichomes, and the perianth also is smooth 

 and free from viscidity. The peduncles alone are 

 furnished with glandular hairs, which stand out 

 horizontally, and prevent small animals from creep- 

 ing up to the flowers, which are rich in nectar and 

 adapted to flying insects. Brosophyllum lusitanicum 



^ In this plant, as soon as the blossoming is over, and a disturb- 

 ance of the flower by creeping insects is no longer a matter that needs 

 to be guarded against, the colloidal layer dries- np and ceases to be 

 sticky. In other cases, on the contrary, the viscidity of the secretion 

 continues even after the blossoming period ; thus in Linncea iorealis 

 L. (Plate I. figs. 12, 13), -which -will be mentioned again on a later 

 page, as also in Plumbago europcea L. (Plate I. fig. 32), and in other 

 species of Plumbago and several species of Salvia, the same colleters, 

 vrhich at the period of flowering keep'oflf creeping animals, contri- 

 bute at a later period to the dispersal of the seed by means of 

 animals. On many fruits, also, as for example on those of Adeno- 

 oarpus, colleters are to be found which are not developed till the 

 flowering is over, and which only discharge thet viscid substance, 

 by means of which they stick to animals, when the fruit is mature. 



