LEAVES INSTEAD OF PETALS 87 
mon Daisy (Bellis perennis) the outer flowers have 
each a long strap-shaped expansion of the corolla, 
which is of a different colour (white) from that of the 
corollas of the inner flowers, which are yellow. In the 
Dandelion (Taraxacum officinale) all the flowers have 
a yellow strap-shaped corolla. In the Guelder Rose 
(Viburnum Opulus) the outer flowers are entirely 
devoted to advertisement, consisting each of a big 
white corolla, while only the small inner flowers pos- 
sess stamens and pistil and are capable of producing 
the brilliant scarlet berries. In a cultivated form of 
this, commonly called the Snowball Tree, the adver- 
tisement flowers only are present, forming a globe of 
white blossom, and no fruit is produced in conse- 
quence. The Dwarf Cornel (Cornus suecica), a little 
Dogwood growing on many Scottish moors, bears 
what looks like a white flower with a purple centre. 
On examination it is seen that the four white petal-like 
structures are really foliage-leaves, which have taken 
on the duty of advertising the group of small purple 
blossoms which they enclose (Fig. 16). A similar and 
very gorgeous effect is produced in several Spurges 
often seen in greenhouses, such as Euphorbia fulgens, 
E. splendens, and E. punicea; in these the upper 
foliage-leaves are large and coloured brilliant scarlet, 
the flowers which accompany them being quite small. 
These aggregations of flowers with their flaunting 
flags are in general an invitation to all comers; the 
nectar in the blossoms lies open to every hungry 
insect, and pollination is effected in a rather promis- 
cuous and messy way; not only flying insects—bees, 
butterflies, beetles, and flies of many sorts—but also 
ants and other creatures which creep up the stems 
