CHAEAOTEES OF CLASSES AND OEDBES. 425 



Class II. Mouoootyledones or Eudogenae. 

 Sub-class 1. Petaloideae. or Floridse, Floral envelopes verticiUate. 



a. Hermaphrodite, ovary inferior. 



h. Hermaphrodite, ovary superior. 



c. Unisexual, often achlamydeous. 

 - — 2. Glumiferse, Floral envelopes imbricated. 



B. Cktptooamous, oe Aootyledonous Flowbbless Plants. 

 Class III. Acotyledones or Acrogense. 



Sub-class 1. jEtheogamae or Cormogense Having vascular tissue. 



2. Amphigamse, ThaUogense, or Cellulares Entirely cellular. 



CHAPTER II. 



AEEANGBMEUT AND CHAEAOTEES OP THE CLASSES AND 

 NATUEAL OEDEES. 



Sub-Kingdom I. — Phaneeogamous Plants. 



Plants producing Sta/mens and Pistils. 



Class I. — Dioottledones and Exogbn^, Juss. axiADC; Aoeamphibrta, .Brefi. 



This is the largest class in the vegetable kingdom. The plants 

 included under it have a cellular and vascular system, the latter con- 

 sisting partly of elastic spiral vessels, (Fig.- 51, p. 17). The stem is 

 more or less conical, and exhibits wood and true bark. The wood is 

 exogenous, i.e. increases by additions at the periphery, the hardest part 

 being internal (p. 49, et seq.). It is arranged in concentric circles. 

 Pith exists in the centre, and from it diverge medullary rays. The 

 bark is separable, and increases by additions on the inside. The epider- 

 mis is furnished with stomata (p. 28). The leaves are reticulated 

 (p. 84), usually articulated to the stem. The flowers are formed upon 

 a quinary or quaternary type, and have stamens and pistils. The 

 ovules are either enclosed in a pericarp, and fertilised by the applica- 

 tion of the pollen to the stigma, or they are naked and fertilised by 

 the direct action of the poUen. The embryo has two or more opposite 

 cotyledons, and is exorhizal in germination (p. 41). 



Sub-class 1. — Thalamifloe^.* 

 Calyx and coroUa present ; petals distinct, t inserted into the 



* Thalamus, receptacle, andjSos, flower. 



t Sometimes the petals are abortive, and it is then difficult to determine whether the 

 plant belongs to this sub-class or to Monoohlamydefe. 



