370 



TERATOLOGY — COHESION AND ADHESION. 



cohesion of two leayes by their bases forms a connate leaf, and the 

 union of the lobes of a single leaf on the opposite side of the stalk 

 gives rise to perfoliate leaves (fig. 171, p. '89). The union of the 

 edges of a folded leaf forms Ascidia, or pitchers (figs. 200, 203, pp. 

 95, 96). The diflferent parts of the same verticil of the flower unite 

 often more or less completely, giving rise to a monophyllous or gamo- 

 phyllous involucre (p. 190) ; a monosepalous or gamosepalous calyx 

 (fig. 297, p. 197; a monopetalous or gamopetalous corolla (figs. 318, 

 319, p. 206) ; monadelphous (figs. 338, p. 213 ; 346, 1, p. 218), 

 diadelphous (p. 218), and polyadelphous (figs. 347, p. 218; 651) 

 stamens ; syngenesious anthers (p. 227) ; a gynandrous column (p. 

 220), and a syncarpous ovary (fig. 417, p. 239). The different verti- 

 cils of the flower are frequently adherent. The calyx is often united 



<SiN 



Fig. 651. 



Fig. 652. 



to the coroUa or to the stamens, or both (fig. 339, p. 213); the sta- 

 mens may adhere to the corolla (fig. 652) ; or there may be a union 

 of the torus with the ovary, so that the calyx becomes superior (fig. 

 340, p. 214). In some instances, when the axis is elongated, adhesions 

 take place between it and certain whorls of the flower. Thus, in some 

 Caryophyllacese (fig. 653), the calyx, c, bearing the stamens, e, and 

 petals, J), becomes united to the axis, g, which supports the ovary, o. 

 In Oapparidacese (fig. 654), the calyx, c, and petals, f, occupy their 

 usual position, but the axis is prolonged in the form of a gynophore, 

 ag, to which the stamens, e, are united. Occasionally, contiguous 

 flowers may unite, giving rise to double fruits, as is sometimes seen in 

 Apples, Grapes, and Cucumbers. 



Multiplication, or an increase of the number of parts, gives rise 

 to changes in plants. It is often found that in plants belonging to 



Fig. 651. One of the five bundles of stamens taken from the polyadelphous flower of 

 Malva miniata. Stamens are united by their filaments. Fig. 652. Portion of the gamo- 

 petalous or monopetalous corolla, p, of a CoUomia, showing part of the tube, (, terminated 

 by two lobes of the limb, I, and having the stamen, e, inserted into it, and united to it, so 

 that the upper part of the filament, i, only is free. 



