UNION OF PARTS. 181 



in the next paragraph, do not mean that the parts were once sepa- 

 rate and have since united. That is true only of certain cases. The 

 union is mostly congenital, equally so in the disks of foliage of 

 the Honeysuckle (Fig. 215) and in the corolla of a Convolvulus. 

 The lobes which answer to the tips of the constituent leaves of 

 the cup or tube are usually first to appear in the forming bud, 

 the undivided basal portion comes to view later. It might be 

 more correct to say that the several leaves concerned have not 

 isolated themselves as they grew. Accordingly, Dr. Masters 

 would substitute for coalescence and adnate the term mseparate. 

 But the common language of morphology needs no change, as it 

 consistently proceeds on the idea, and the prevalent fact, that 

 leaves are separate things, and that the tube, cup, or " inscpa- 

 rate " base of a calyx or corolla, consists of a certain number of 

 these. It is no contradiction to this view that they developed 



3. UNION OF DISSIMILAR on SUCCESSIVE PARTS. 



33 1 . Actuation is the most appropriate term to denote the organic 

 and congenital cohesion or consolidation of different circles, the 



1 If it were seriously proposed to change the language of descriptive 

 botany in this regard, consistency would require its total reconstruction, with 

 the abolition of all such terms as deft, parted, &c. ; for the structures in 

 question are no more cleft than they are united. While these convenient 

 and long-familiar terms are continued in use (as they surely will be), although 

 quite contrary to literal fact, it cannot be amiss to continue those, such as 

 connate, adnate, coalescent, &c., which imply and suggest the fundamental fact 

 in the structure of phaenogahious and the higher cryptogamous plants, viz. 

 that leaves are normally unconnected organs. 



Whether fusion or separation is the more complex condition, and therefore 

 indicative of higher rank, is a question of a different order. It is argued 

 that the fusion or lack of separation is an arrest of development, and there- 

 fore an indication of low rank or less perfection than the contrary. But a 

 phylogenetic view of the whole case may reverse this conclusion as respects 

 the blossom. The course of development from thallus and frond to distinct 

 foliage on an axis, from little to full differentiation, is clearly a rise in 

 rank, as also is the differentiation of foliage into ordinary leaves, petals, 

 stamens, and pistils. But there is as much differentiation in the flower 

 of a Convolvulus as of a Ranunculus, and more in that of a Salvia, a 

 Lobelia, and an Orchis. In all such flowers, the combination, the irregu- 

 larity, and the diversification in many cases of the members of the same circle, 

 all indicate complexity, greater specialization, and therefore higher rank. 

 The production of leaves distinct from the axis is one step in the ascending 

 scale : such specializations and combinations of these as occur in flowers are 

 higher steps ; and the most specialized, complex, and therefore highest in 

 rank are complete, corolliferous, irregular flowers, with a definite number of 

 members, and these combined in view of the adaptations by which the ends 

 of fertilization and fructification are best subserved. 



