126 



CHAPTER II. PRINCIPAL SUB-DIVISIONS OF THE 

 VEGETABLE KINGDOM. 



. . 111. All plants are first divided 



-Division , .-I i i i i-i-i 



of the into the two great groups, or sub -kingdoms, called respec- 



Vegetabie tively Cryptogams and Phanerogams. The term Cryptogam 

 is derived from two Greek words signifying " hidden mar- 

 Cryptogams riage " and was originally applied to all plants whose reproduc- 

 and tive organs were minute and inconspicuous. 



Phanero- 

 gams. From the absence of what are usually called flowers, or 



structures containing stamens, or pistil, or both, this great 

 group of Cryptogams is sometimes referred to as the one 

 containing " flowerless," or " non-flowering," plants, while the 

 group of Phanerogams is similarly termed that which includes 

 the " flowering " plants. 



The essential difference between Cryptogams and Phanero- 

 gams, however, consists in the fact that the latter produce 

 true seeds, i.e. many-celled bodies containing the multi- 

 cellular embryo or young plant, whereas Cryptogams, in place 

 of seeds, produce spores which are unicellular structures. 

 These spores may be developed asexually, or they may arise 

 as the result of a sexual process, the latter being manifest in 

 the mingling together of the protoplasmic contents of distinct 

 cells. When the sexual cells are externally similar, each is 

 termed a gamete, when one is smaller and more active than the 

 other, the small active cell is termed the spermatozoid, and 

 the large passive cell the egg-cell, or oosphere. Spores which 

 are capable of remaining dormant for considerable periods are 

 distinguished from those capable of germinating immediately 

 after their formation by the name of resting spores. 



the 112 ' These tw g reat g r U P S are 



Cryptogams, further sub-divided as follows : 



CRYPTOGAMS. 



I. THALLOPHYTA. ") Cellular plants with no true vas- 

 II. BRYOPHYTA. j cular bundles. 



III. PTERIDOPHYTA. Vascular plants with true vas- 

 cular bundles. 



Thaiio- THALLOPHYTA. The plants in this group show no distinct 



phytes. differentiation into stem and leaves and the cellular body 



