68 NATURE STUDY AND AGRICULTURE 
the end of the main stalk so as to resemble the ribs of an 
open umbrella. 
All the plants of the carrot family have 
this sort of flower cluster, and it is 
also seen in the common milkweed 
and in some other plants. 
The S pike and the Catkin.— In the 
spike the flowers are close together 
and so close up to the central stalk 
that we cannot see their little stems, 
if they have any. x 
The plantain fur- 
ComMON PLANTAIN nishes a good eX- 
Flower clusters in the form ampl e. The so- 
of spikes. 
wheat, barley, and rye are spikes in which the 
called ‘‘ heads” of 
flowers are not attached to the central stalk pussy Wittows 
singly but in small clusters called spikelets. Left, pollen- 
Heaps 
a. Red clover. 
b. Sunflower. 
bearing —catkin. 
Right, seed-bear- 
to the flower cluster of the ingcatkin. Notice 
willow, poplar, cottonwood, te tiny pods. 
and some other trees. It is a scaly sort of 
spike. 
The Head.— Here all the flowers are 
attached to the end of the flower stalk, giving 
a compact cluster that is easily taken for a 
single flower by the untrained observer. 
Clover blossoms furnish a simple example. 
But the more common kind of head we find 
in the composites, as sunflowers, dandelions, 
etc. In these the summit of the flower 
stalk is flattened into a broad disk which 
bears the flowers upon its surface. 
Catkin is the name given 
