1 62 BOTANY. 



will usually be found on different branches of the same 

 tree. And, while you are searching for their flowers, ob- 

 serve also their remarkable foliage. Fig. 438 shows a fas- 

 cicle of needle-leaves from the pine. Observe the number 

 of leaves in each fascicle of the specimen you are study- 

 ing, for the species vary in this respect. Fig. 439 repre- 

 sents the scale-shaped leaves of arbor-vitas. In ever- 

 greens of this sort observe the difference between the 

 foliage on the older and newer parts of the plant. In 

 dioecious species, observe whether the foliage is of the 

 same kind on both $ and $ plants. When you find awl- 

 shaped leaves upon a young branch, observe them from 

 time to time, and note their gradual passage into scale- 

 shaped, imbricate leaves. Do evergreens shed their foli- 

 age ? If so, when ? and how long does the foliage last ? * 

 Can you find young foliage upon old branches ? 



In the pine the inflorescence of the sterile flowers is a 

 kind of compound spike (Fig. 440). One of the spikelets 

 much magnified is shown in Fig. 441. Each flower of this 

 spikelet consists of a single stamen only, and this stamen 

 has a most peculiar structure. Its filament is so short as 

 to be scarcely discernible. It is really a spikelet of an- 

 thers, and their connective. Remove a stamen, and ex- 

 amine its inner face. Compare it with Fig. 442, which is 

 a $ flower of the pine. Here you see two anther-cells 

 dehiscing vertically, and Fig. 443 represents a grain of the 

 compound pollen they bear. Seen on . the outside, this 

 stamen appears to be all connective. This connective, or 

 scale, as it is usually called, varies in form in different 



* To find whether evergreens shed their foliage, you have only to 

 watch the ground beneath them for fallen leaves. If you find that 

 their foliage does fall, and wish to learn by observation how long it 

 lasts, notice whether the twigs of the present year keep their foliage 

 all through the coming winter. If they do, observe them again next 

 summer, and if it is still retained, watch them the third season, and so 

 on. 



