THE PLAN OF THE FLOWER. 85 



3. Redundancies, 



a, In the multiplication of organs, 

 6, In appendicular organs. 



4. Union of parts. 



a, By cohesions, 

 6, By adhesions. 



5. Irregularities of development, 



a, In homogeneous parts, 

 6, In the receptacle. 



6. Combined deviations. 



We shall consider these several topics in their order. 



418. THE RADICAL NUMBER OF THE FLOWER is that which enumerates the parts 

 composing each whorl. It varies from one to twenty, and is expressed thus: 

 V, \/, V, V, etc., which mathematical expressions are to be read by the words, 

 dimerous (dt, two, /uspof, part), or 2-parted ; trimerous, or 3-parted ; 4-merous, or 

 4-parted ; pentamerous, or 5-parted ; 6-merous, or 6-parted, eta 



419. EXOGENS AND ENDOGENS DISTINGUISHED. Pentamerous (V) flowers, like 

 the rose, flax, when each whorl is (naturally) 5-parted, are more generally charac- 

 teristic of the exogenous plants, V flowers of the endogens, as the lily, Trillium. 

 The flowers of Fuchsia are V, of Circaea V, and of Hippuris 1 V. 



420. DEFICIENCIES. Incomplete flowers often occur. They lack some one or 

 more entire sets of organs. When only one of the floral envelops, the calyx, ex- 

 ists, the flower is said to be apetatous or monochlamydeous (xhapve, a cloak), as in 

 elm, Phytolacca. These terms are also loosely applied to such plants as rhubarb, 

 Anemone, liverwort, where the pieces of the perianth are all similar, although in two 

 or three whorls. When the perianth is wholly wanting, the flower is said to be 

 achlamydeous or naked, as in lizard- taiL (264.) 



264, Flower of Saururus (lizard-tail) ; achlamydeous. 265, Flower of Fraxinus (ash). 266, 

 Flower of Salix (willow), staminate. 267, pistillate. 



421. IMPERFECT FLOWERS are also of frequent occurrence. They are deficient in 

 respect to the essential organs. A sterile or staminate flower (denoted thus ) has 

 stamens without pistils. A fertile or pistillate flower ( $ ) has pistils without sta- 

 mens. Such flowers being counterparts of each other, and both necessary to the 

 perfection of the seed, must exist either together upon the same plant or upon sep- 

 arate plants of the same species. In the former case the species is monrecious (g ) 

 as in oak ; in the latter case dioecious ( $ $ ) as in willow. The term diclinous, de- 

 noting either Q or $ $ without distinction, is in common use. 



