18 PRACTICAL BOTANY. 



II. Flokideous Sub-class. 



54. The plants of this sub-class usually have perfect 

 and complete flowers, with a perianth divisible into two 

 3-leaved whorls, both sometimes green, more often the 

 outer one only. 



Oedees : 



116. Water-plcmtodns, AUsmaoem ; 111. Frog-hits, ITy- 

 drocha/ridacecB ; 118. Burmcmniads, £urmanniacecB / 

 119. Orchids, Orchidacem; 120. Ama/ryUids, AmarylU- 

 dacece; 121. Bloodworts, JIoefmodoracecB ; 122. Brome- 

 liads, BromeUacem ; 12Z. Irids, Tridwem ; 124. Yam- 

 roots, BioscoreacecB ; ^ 125. Sarsa/parUlas, SmUaceoe; 

 126. Lilyworts, LiUaceoB ; 127. Melcmths, Mela/nthaceoB ; 

 128. HusJies, .Jmicaceos ; 129. Pontederiads, or Pick- 

 erel-weeds, PontederiaceoB ; 130. Spiderworts, Comme- 

 lynacece; 131. Xyrids, Xyridacem ; 132. Pipeworts, 

 EriocaulonacecB. 



III. GLUMAcfiours Sub-class. 



55. The plants of this sub-class have flowers with an 

 imbricated perianth of alternate glumes, instead of sepals 

 and petals, and collected into spikelets, spikes or heads. 



Oedees : 



133. Sedges, Oyperacece ; 134. Cfrasses, Grmtiineae. 



(These 134 orders are enumerated in the same sequence, 

 as in A. Grcmj's Manual^ 



56. A Natwral System, such as we have .just dis- 

 played, has for its basis the whole plan of structure, so 

 that each genus, tribe, and order is placed next to those 

 genera, tribes, and orders which it most resembles in all, 

 or nearly all, respects. In Aetifioial Systems, on the 

 other hand, the real nature of the plants is disregarded, 



