416 SYSTEMATIC BOTANY. 



more highly developed than in any other member of the Vegetable King- 

 dom. Passing over the less sharply marked degrees in the scale, repre- 

 sented by other Vascular Cryptogams, we come to the Mosses, in which, 

 though stems and leaves are present, we lose sight of the true root, the 

 place of which, however, is supplied by organs of corresponding physiolo- 

 gical value. In the stems and leaves, too, we no longer find the relations 

 so perfect, since there is no perfectly organized vascular tissue, but only 

 an indication of it. The anatomical structure of the Hepaticce is com- 

 paratively still lower in the scale, and approaches that of the Thallo- 

 phytes more nearly than any other Cormophyte. The life-history of 

 Cormophytal Cryptogams consists of two distinct generations a sexual 

 alternating with an asexual one. 



Division I. Vascnlaria. 

 Cormophytal Cryptogams possessing vascular tissue. 



The Vascular Cryptogams consist of the Equisetacece, the Filices, the 

 Lycopodiacece, the Selaginellacece, and the Rhizocarpece. Their life-history 

 is composed of two alternating generations an asexual and a sexual. 

 The asexual generation is that in which the plants are commonly seen and 

 known, and during which they attain the highest point of development in 

 their vegetative structure. They possess in this stage both cellular and 

 vascular tissues, organized in some cases (the Filices) on perhaps the most 

 perfect system possessed by any known vegetable. Shortly stated, their 

 life-history begins with the germination of an asexually produced spore, 

 which gives rise to a prothallium (usually a mere layer of simple cells 

 so organized as to sustain an independent life), on which are borne 

 antheridia (male organs) or archeyoma (female organs). The antheridia 

 produce antherozoids or spermatozoids, as they are differently named, which 

 fertilize the archegonia out of which the asexual spore-bearing generation 

 springs (see fig. 493, p. 410). 



The Vascular Cryptogams are divided into five Orders as follows: 



Equisetacese. ) 



Fiiices. > Spores of one kind. 



Lycopodiaceae. ) 



Series 1. ISOSPOEIA. 



Vascular Cryptogams producing spores of one kind only. Pro- 

 thallium growing free from the spore and producing antheridia and 

 archegonia. 



EQUISETACEvE. THE HOESE-TAIL OKDEE. 



Diagnosis. Asexual Generation : Herbaceous plants with jointed, 

 subterraneous rhizomes, sending up at intervals fistular-jointed 



