22 
POPULAR SCIENCE REVIEW. 
delicate cellular tissue or epidermis. At the summit, the 
flower-stalk expands into a receptacle, which is of a conical 
form, and at first is filled up internally with cellular tissue. 
When the flowers and fruit have been perfected and fallen off, 
we find the receptacle left, and that it has become hollow like 
the stalk. At first the receptacle presents the form of a small 
protuberance, but as it gets older it assumes more of a sugar- 
loaf appearance, which is very decided when the flowers and 
fruits have fallen from it. 
Around the receptacle are placed the bracts in two rows, one 
behind the other, forming an involucre, or, as botanists call it 
where the bracts overlap, a Phyllary. These bracts number 
from twelve to fifteen. In order to examine them perfectly we 
must use the microscope. Under a quarter-inch object-glass, 
we observe the centre portion of the bract to be denser and of a 
deeper green than the outer edges, which are almost transparent 
(fig. 3). The cellular tissue (fig. 5) of which they are composed 
is elongated at the margins into delicate hairs ; this condition of 
the edges of the bracts, produced by the absence of cMorophyle 
(the green colouring matter of the leaf), when very decided, is 
known by the term scarious. The surface of the bract is rami- 
fied with delicate veins r unni ng symmetrically on each side of 
the centre vein, and the intervals present stomates such as we 
have seen on the leaves. 
The receptacle on which the flowers are placed is covered 
with little elevations which, when the flowers die and fall off, 
mark the places where they stood (fig*. 6). 
In common with the rest of the tri he Aster ctcece, the flowers are 
of two kinds, ligulate and tubular (fig. 2, a, b). The outer white 
bodies which appear so much like the petals of other flowers, and 
are so frequently mistaken for them, are in reality the ligulate 
flowers of the plant, each perfect in itself. It is almost im- 
possible without a magnifying glass or microscope to compre- 
hend the true nature of these pretty little objects, which are 
well worth careful examination. There is no apparent calyx, 
neither do we find any cpiantity of the downy pappus, so abun- 
dant in some of the Gompositce ; this organ seems to be repre- 
sented by a few little hairs around the tube of the corolla in the 
daisy. The petal-like expansion is the monopetalous corolla 
of this ligulate flower (fig. 7). It is most frequently of a 
white colour, but in a large number of instances the tips of 
flowers will be found to be coloured pink. The pink colour 
sometimes covers the whole of the back of the flower. 
The ligulate flower has no stamens or pollen-bearing organs, 
but has a single pistil which at the top divides into two branches 
forming stigmas (fig. 7). Under the microscope it is evident 
that the pollen grains produced by the tubular flowers, of 
