418 SYSTEMATIC BOTANY. 



2. Sexuax, oe Flowering Plants. 



Fructification springing from a thallus Class 3. Rhizogens. 

 Fructification springing from a stem. 

 Wood of stem youngest in the centre; 

 cotyledon single. 

 Leaves parallel-veined, permanent; 



wood of the stem always confused Class 4. Endogens. 

 Leaves net -veined, deciduous; 

 wood of the stem, when peren- 

 nial, arranged in a circle with 



a central pith Class 5. Dictyogens. 



Wood of stem youngest at the cir- 

 cumference, always concentric ; 

 cotyledons two or more. 



Seeds quite naked . . . Class 6. Gymnogens. 

 Seeds enclosed in seed-vessels . Class 7. Exogens. 



The Exogens were further divided into four sub-classes thus : — 



Sub-class 1. Dicli7ious Exogens, or those with unisexual flowers, 

 and without any customary tendency to form 

 hermaphrodite flowers. 



Sub-class 2. Hypogynous Exogens, or those with hermaphrodite 

 or polygamous flowers ; and stamens entirely free 

 from the calyx and corolla. 



Sub-class 3. Perigynous Exogens, or those with hermaphrodite 

 or polygamous flowers, and with the stamens 

 growing to the side of either the calyx or 

 corolla ; ovary superior, or nearly so. 



Sub-class 4. Ej)igynotis Exogens, or those with hermaj hrodite 

 or polygamous flowers, and with the stamens 

 growing to the side of either the calyx or 

 corolla ; ovary inferior, or nearly so. 



Neither of the other classes are divided into sub-classes, but 

 of Endogens, four sections are distinguished thus : — 



1. Flowers glumaceous; (that is to say, composed of bracts not 



collected in true whorls, but consisting of imbricated 

 colourless or herbaceous scales). 



2. Flowers petaloid, or furnished with a true calyx or corolla, 



or with both, or absolutely naked ; unisexual (that is, 

 having sexes altogether in different flowers, without half- 

 formed rudiments of the absent sexes being present). 



3. Flowers furnish-ed with a true calyx and corolla, adherent to 



the ovary ; hermaphrodite. 



4. Flowers furnished with a true calyx and corolla, free from 



the ovary ; hermaphrodite. 



