THE BAHAMA FLORA 



All plants may be grouped in four main categories, known as 

 Phyla or Subkingdoms, as follows: 



Phylum 1. Spermatophyta, those which bear seeds, a seed 

 being different from all other vegetable structures by containing 

 an embryonic plantlet. All spermatophytes bear flowers of one 

 kind or another, and this phylum is also called Anthophyta, or 

 flowering plants and, to distinguish it from the three other phyla 

 collectively, Phanerogamia. Phyla 2, 3 and 4 taken together are 

 called Cryptogamia; all these are seedless. 



Phylum 2. Pteridophyta, comprises ferns and fern allies; 

 all are flowerless and have two separate and distinct alternating 

 generations, the one represented by the fully developed plant 

 having root, stem and leaves, with vascular tissue and bearing 

 spores, a spore being a single vegetable cell capable of growing 

 into a new plant ; the other, called the prothallium stage, is smaU, 

 inconspicuous, grows from the spores, has no vascular tissue, is 

 not differentiated into root, stem and leaves, and bears the sexual 

 organs; from the female organ of the prothallium (arehegonium) 

 the fully developed spore-bearing plant again arises; the male 

 organ, borne either on the same prothallium or on a different one, 

 is called an antheridium. 



Phylum 3. Bryophj^a, consists of mosses and their allies; 

 all are small flowerless plants with alternating sexual and non- 

 sexual (spore-bearing) generations, but the spore-bearing genera- 

 tion never becomes separated and independent; the sexual gen- 

 eration is commonly the more conspicuous and is, in most cases, 

 differentiated into stem and leaves, while the spore-bearing gen- 

 eration is never thus differentiated ; their spores are borne in con- 

 ceptacles termed capsules, and from the spores the plant again 

 develops. Bryophytes consist almost wholly of cellular or non- 

 vascular tissue. 



Phylum 4. Thallophyta, includes the algae, fungi and lichens ; 



