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270 THE FERTILISATION OF FLOWERS. [parr m1. j 
e.p. only ; (5) H. sexnotatus, K. 9, cp. only ; (6) Ceelioxys simplex, Nyl. 
2,8.; (7) Apis mellifica, L. $, cp.; (6) Sphegidw: (8) Gorytes mystaceus, 
L., freq., s.; (9) Ammophila sabulosa, L., freq.,s.; (c) Vespide : (10) Eumenes 
pomiformis, L. ¢; (11) Odynerus parietum, L.?, both sucking. B. Coleoptera 
—Malacodermata : (12) Dasytes sp., only on the male flowers, fp. C. Lepi- 
doptera—Rhopalocera: (13) Pieris napi, L.,s. See also No. 590, 11. 
The flowers of a species of Zrianosperma in South Brazil are 
visited, according to Fritz Miiller, very abundantly all day long by — 
Apis mellifica and species of Melipona, although they are scentless, 
greenish, quite inconspicuous, and to a great extent hidden by 
foliage (597). 
Orv. UMBELLIFERL. 
The general phenomena of pollination in Umbellifere have — 
been already so clearly and thoroughly described by Sprengel, that 
I may confine myself to a short account of the most important — 
peculiarities. The main features of the flowers are: firstly, the 
open situation of the honey, making it accessible to even the most 
short-lipped insects; and secondly, the union of many flowers in 
one head, making them not only more conspicuous, but also per-— 
mitting them to be more quickly searched and fertilised. Cornus 
shares both of these characters with the Umbelliferz, but in a 
much less perfect form. 
In most Umbellifers the honey is rendered even more accessible — 
than in Cornus, by the secreting disk being more convex and — 
cushion-shaped, and by the stamens spreading further apart. The — 
close association of many flowers is more perfectly attained in 
Umbelliferze than in Cornus, far more numerous flowers uniting in 
one close-set surface, so that a visitor quickly traverses the whole ; 
and the florets are differentiated in the service of the community, 
those in the centre being condensed, and those towards the edges 
more expanded, rendering the whole more conspicuous. 
As a further advantage comes proterandrous dichogamy, often 
developed to such a degree that all the florets of one whole in-— 
florescence only protrude their styles and develop stigmas after 
the shedding of the pollen : so that in the first period of flowering © 
a whole community dusts with pollen the insects that visit it, and 
in the second, exposes its stigmas to be dusted in return. So cross- 
fertilisation of separate inflorescences always takes place, and the 
impossibility of self-fertilisation is still further assured. Hence it 
happens that in many Umbellifers (e.g. Myrrhis) towards the end 
of the season only male flowers are produced, which furnish. pollen 
