SYNOPSIS OF THE ORDERS OF PLANTS CONTAINED IN VOLUME XII 



OF THE SILVA OF NORTH AMERICA. 



Class III. GYM NO SPERMS. Resinous trees or shrubs. 



Stems increasing in diameter by the annual addition of a layer of wood inside the bark. Flowers unisexual, naked. 



Stamens numerous. Ovules 2 or many not inclosed in an ovary. Cotyledons 2 or more. Leaves usually straight- veined, 

 persistent, or deciduous. 



58. Coniferse. Flowers monoecious, usually solitary, terminal, or axillary. Ovules 2 or many. Fruit a woody 

 or rarely fleshy strobile. Cotyledons 2 or many. Leaves scale-like, linear or subulate, solitary or clustered. 



