514 



PART III. THE CLASS [Fl CATION OF PLANTS. 



two perianth- whorls should, if a Monocotyledon, be regarded as 

 being probably dichlamydeous ; whereas, if a Dicotyledon, it 

 should be regarded as probably monochlamydeous, the two whorls 

 representing either a calyx or a simple perianth. 



The individual leaves of the perianth may be either perfectly 

 separate (eleutheropetalous or polypeialous corolla, eleutherosepalous 

 or polysepalous calyx), e.g. Ranunculus ; or they may cohere from 

 the base upwards, so as to form a longer or shorter tube, which 

 divides at its upper end into as many teeth or lobes as there were 

 originally leaves (gamosepalous calyx, gamopetalous corolla) (Fig. 

 329 A B G c and B k) ; e.g. the Primrose and the Tobacco plant. 

 In Dianthus (the Pink) the sepals alone are coherent, as also in 



Daphne (Fig. 329 I)) 

 where the corolla is 

 absent. More rarely 

 all the leaves of the 

 perianth cohere to 

 form one tube, e.g. the 

 Hyacinth and allied 

 genera ; the six lobes 

 of the tube correspond 

 to the three sepals 

 and the three petals. 

 The simple perianth 

 also may consist of 

 separate leaves (eleu- 

 theropJiyllous or poly- 

 pTiijllous perianth), e.g. 

 Amarantus, or the 

 leaves may be coher- 

 ent (gamophyllous) t e.g. 

 Aristolochia. 



D 



FIG. 329. Cohesion of sepals and petals. A Flower of 

 Convolvulus arvensis, with a funnel-shaped corolla (c); and 

 a 6-partite calyx (fc). B Nicotiana Tabacum, with a5-cleft 

 calyx (fc) ; tubular corolla (f), with a distinct 5-toothed 

 limb (s). C The rotate corolla of Sambucus. D Gamose- 

 palous calyx of Daphne Mezereum ; r the tube; s the limb. 



The degree of division presented by gamophyllous perianths into teeth or 

 lobes is indicated by the same terms which are used in describing the incision 

 of the leaf-blade (page 54). The form of the gamopetalous corolla may be 

 campanulate, as in the Campanula ; funnel-shaped (or infwidibuliform), as in 

 the Bindweed (Fig. 329 A)\ totate, as in the Elder (Fig. 329 C). The upper 

 and lower portions may frequently be distinguished, the lower as the tube (Fig. 

 329 B r), the upper expanded part as the limb (Fig. 329 B s). Other peculiar- 

 ities of form are connected with the symmetry of the flower (page 511). 



The petal frequently consists of two parts, the daw and the 



