ESSENTIAL FLORAL LEAVES. 99 
and female, with carpels only. Several terms used in this con- 
nection, are given in the following table :— 
monecious, with both kinds 
on same plant, e.g., fir, 
hazel, arum; diwcious, 
with the two kinds on 
different plants, e.g., wil- 
low, nettle, hop. 
unisexual flowers are 
Plants possessing 
unisexual flowers + bi- 
sexual flowers are 
polygamous, e.g., ash. 
The instances mentioned may now be briefly described. 
Fir (fig. 45).—Male cones small, crowded into a cluster on the 
sides of a shoot which produces leaves beyond it. Dusty when 
ripe from yellow pollen. Female cones occur singly for the most 
part. They take two years to mature their seeds, and in early 
summer cones in three stages may be found on the same plant. 
(1.) Small green cones with pink-tipped scales, occurring close to 
the ends of the youngest shoots, and belonging therefore to the 
current year. (2.) Larger green cones, belonging to the previous 
year, and situated on older shoots. (3.) Brown woody cones with 
ripe seeds, placed on still older parts of the stem, and two years 
old. 
Hazel.—The pendent catkins seen in March are male inflores- 
cences, and consist of a large number of scaly bracts. Each of 
these bears four stamens on its under side, but, as each of these 
is forked, there appear to be eight. ‘Their true nature is shown 
by the fact that they bear but one anther lobe. The female cat- 
kins are very small, and being closely surrounded by bracts, look 
like buds. ach of them consists of five or six flowers, the only 
parts of which are visible externally resemble a number of small 
threads, bright pink in colour. 
Arum (fig. 33).—The upper part of the spadix is club-shaped 
and brightly coloured. Lower down comes a circlet of aborted 
male flowers, a little distance beneath which is a lot of small male 
flowers, each of which consists of one stamen. These are crowded 
into a ring round the stem. A ring of female flowers forms the 
base of the inflorescence. It is separated by an interspace from 
the preceding. Hach female flower has a single carpel, but, like 
the male flowers, is devoid of perianth. Those at the upper part 
of the ring are aborted. 
Willow.—Both male and female catkins are here short and 
upright. The former are readily distinguished by their bright 
yellow colour, and consist of a large number of male flowers with- 
out perianth. Hach consists of two long stamens placed in the 
axil of an oval bract provided with long hairs. At the base of 
