92 BRITISH FLOWERING PLANTS chap. 



folded on itself, cut into the form shown in Fig. 53, A, 

 with the fold along the edge from in to h, and then 

 unfolded, the reason for the form of the cotyledon 

 becomes clear at once. 



EESEDACE^ 



Eeseda (Mignonette) 



In this genus the flower-bud is open, and the maturity 

 of the flower is indicated by the appearance of honey 

 which is secreted in a cup-shaped cavity of the disk, 

 covered over by the three upper petals, which form a 

 lid completely closing the nectar -holder. It is thus 

 contained within a closed box, the lid of which must be 

 prised up before it can be removed. According to 

 Miiller, the most frequent visitor is the bee Prosopis, 

 which has a flat trowel-shaped proboscis which it uses 

 in plastering its cell. The nectar-gland bears such an 

 obvious correlation to this form of proboscis as to favour 

 the conclusion that in Eeseda we have a flower specialised 

 for cross -fertilisation by short-lipped bees.^ The seeds 

 are black, smooth, and shining, and so much curved as 

 to be nearly circular in outline. 



R. lutea. — The flower is scentless and yellowish green. 

 The anthers open at the time when the secretion of 

 honey commences, and the stamens bend towards the 

 pistil. The stigma ripens simultaneously so that self- 

 fertilisation can easily take place. A.t the same time, 

 according to Darwin," it has generally little or no efi'ect. 

 The honey, however, attracts many small insects, which 

 bring pollen from other flowers. The petals are peculiar. 

 They consist of three upper lobes, of which the central 

 is narrow and club-shaped, and a lower flap which serves 

 to protect the honey. The leaves are much divided. 



E. Luteola (Dyer's Weed) has entire leaves, and the 

 flowers form long, pointed spikes. 



^ Reijort, Britisli Association, 1883, "On the Nectar Gland of Reseda," by 

 Professor A. S. Wilson, M.A. 



^ He also found the Garden Mignonette {R. odorata) to be self-sterile. 



