Trees of the Northern Umtkh States 



viduals the plant is diecious. In this case the plants are spoken 

 of as staminate trees and carpellate trees. 1'he stamens 

 produce microsporangia and the carpels megasporan ;ia or 

 ovules. In the anthophyta the carpel usually has three parts 

 called stigma, style, and ovulary, the ovules being ccmplelrely 

 inclosed in the ovulary. Commonly all the carpels of tlie 

 gynecium are grown together and in such cases a compound 

 ovulary is produced with one or more cavities. 



h'ollowing a peculiar process known as the reduction 

 (livi>ic)n which takes place in the cells inside of the micro- 

 sporangium, a considerable number f)f microspores are de- 

 \eloped. four, for each original cell. In nearly the same 

 way, four nu-gaspores, one of wliich survives, are usually 

 produced in each ovule. The flowers are thus modified spore- 

 bearing branches or shoots producing two kinds of nonsexual 

 spores. The flowers are nonsexual organs and the tree itself 

 is always a nonsexual plant called the sporophyte, although 

 some of its parts may show sexual characters and dimorphism. 

 Tlie microspores germinate and develop into the pollen grains 

 and the megasporcs into the so-call,cd embryo sacs, or minute, 

 ])arasitic, male and female gametophytes respectively, which 

 are the real sexual generation. After pollination has taken 

 place, which is simply the transfer of the pollen to the ovules 

 or to the stigmas, a tube grows from the pollen grain into tlte 

 embryo sac. The two sperm cells produced in the pollen 

 grain or in the pollen tube pass down the tube and one unites 

 with the egg cell of the female gametophyte. This unicn of 

 sperm and egg is called fertilization. The resulting cell which 

 is the oospore germinates and gives rise to an embryo inside 

 of the ovule, the whole finally constituting the body called the 

 seed. In the anthophyta, endosperm is produced in the seed 

 l)y the union of the second sperm with two cells from the 

 female gametophyte. This embryo in the seed is the spo- 

 rophyte and after sprouting develops into the tree. The seed 

 is produced inside of or in connection with the modified 

 carpels and other contiguous parts, the whole being called 

 the fruit. The fruits of our trees are of many types usually 

 with some adaptation for seed distrilnition. so tl^at the seed 

 with its little embryonic tree inside may l)e carried away from 

 the parent plants to some other and perhaps more favorable 

 environment. Here, if conditions are proper, it sprouts and 



