parrut] § THE MECHANISMS OF FLOWERS. - 89 
_ Agquilegia, or irregular, as Delphinium and Aconitum ; and so we 
. may conclude that in the Ranunculacee the certainty of cross- 
fertilisation has been more effectually attained by flowers being 
_ specially adapted for a few species of bees, than by attracting a 
great multitude of different guests. We must however beware 
_of taking this as a general conclusion; for in Umbelliferze the still 
more open situation of the honey, aided by the massing together 
of many flowers, insures cross-fertilisation, through proterandrous 
dichogamy, even so far as to permit loss of the power of self- 
- fertilisation. 
Only those Ranunculacer seem to me to be adorned with 
- blue colours which are cross-fertilised by bees, eg. Hepatica 
_ triloba, which is fertilised by pollen-collecting bees, or the 
species of <Aquilegia, Aconitum, and Delphinium, which seem 
adapted for humble-bees by the whole structure of their flowers. 
The easy transition in Hepaticas from blue to pink, and even to 
white, may be most easily explained as a case of reversion (vide 
also 6009). 
Orv, CALYCANTHACEZ. 
Chimonanthus fragrans, Lind., has, according to Hildebrand, pro- 
_ terogynous flowers. In the first stage, the still immature stamens 
are bent away from the stigmas, which receive pollen from other 
flowers; in the second stage, the ripe stamens arch over the stig- 
-mas and prevent access to them (356, p. 491). Delpino saw the 
_ flowers visited by an Osmia at Florence (177, p. 59). 
Calycanthus floridus, L., according to Delpino, is markedly pro- 
terogynous with short-lived stigmas; it is devoid of honey, and 
is probably fertilised by Cetoniw (177, p. 58). 
Orv, MAGNOLIACE ZZ. 
5 Lilicium religiosum has in the middle of the flower, according 
_ to Delpino, little papillae, very rich in honey and resembling 
_ stigmatic papillee, which probably serve as bait for a Cetonia (567). 
i Magnolia Yulan, Desf., is proterogynous. According to Delpino, 
bees fly into the upright flowers, and in the first period are neither 
able to creep up the smooth petals, nor to rise in flight from the 
| _ short pistil which stands erect in the centre of the flower. They 
_ remain prisoners until in the second period the petals spread out, 
5 and the bees then fly away, dusted with pollen, to another aver 
1 (178, 360, p. 593). 
