242 ‘THE FERTILISATION OF FLOWERS. [PART IIT. 
Amelanchier vulgaris, Moench. (Aronia rotundifolia, Pers.).— 
This plant is imperfectly proterandrous. Of the three whorls of 
stamens, the outermost dehisce, while the others are still bent in- — 
wards and shelter the immature stigmas. The inner anthers and 
the stigmas are ripe together (609). 
REVIEW OF THE ROSACE. 
t 
: 
; 
if 
In all honey-yielding Rosacez the honey is secreted and 
carried by an annular region (disk) of the inner wall of the re- | 
ceptacular tube, sometimes closely surrounding the pistil, some- 
times shifted farther outwards: this ridge shows all transitions 
between abundant and evident drops of honey, a thin sweet 
layer invisible to us but eagerly licked by insects, and, lastly, 
absolute barrenness. 
The abundance of insect-visits depends here, as elsewhere, on 
the conspicuousness of the flowers and the amount of spoil they 
furnish ; and, similarly, the variety of insects which frequent the 
flowers ‘depends on the accessibility of the spoil. For instance, 
the small, yellow, honeyless flowers of Agrimonia Hupatoria are 
sparingly visited by a few pollen-feeding Syrphidew and pollen- 
collecting bees; while the equally honeyless roses attract a very 
numerous company of insects, which come for the sake of the 
pollen and the delicate tissues of the flower. The effects of 
conspicuousness are well illustrated by the Raspberry and the. 
Blackberry. The effect of diminished accessibility of the honey 
in restricting the variety of insect-visitors is shown in the case 
of Gewm rivale; the flowers of which remain half-closed, and, 
though yielding abundant honey, are only visited by specially 
long-tongued bees and flies (Bombus and Rhingia): the Rasp- 
berry and Blackberry may be contrasted to illustrate this poin } 
also. 7 | 
In Rosaceze whose honey lies concealed and which are fertilised 
by a motley crowd of short-lipped insects, the flowers are for 
most part greenish-yellow, yellow, or white in colour; in Comarwi 
palustre, Potentilla atrosanguinea, and Sanguisorba officinalis they are 
dark-red or purple, probably owing to the influence of carrion 
feeding flies. | 
In Rosaceze whose honey lies more deeply placed, which aré 
mainly fertilised by long-tongued bees, we find in part red colour 
