OP THE CALYX. 249 



Under ordinary circumstances, the sepals may be 

 considered as the representatives of the sheath of the 

 leaf (cataphyllary) or of the blade (euphyllary), the 

 arrangement of the veins being different in the two 

 cases ; thus, in the vagina or sheath, there are gene- 

 rally several large veins of about equal size, either 

 convergent towards the apex, or divergent; on the 

 other hand, in the blade, there is usually but one 

 central vein, the midrib, larger than the rest, and the 

 smaller veins come off at a less acute angle, and are 

 more reticulated.^ 



Now, when phyllomorphy occurs in sepals which 

 ordinarily are vaginal, it is obvious that the case is one, 

 not merely of increased relative growth, but also of 

 the appearance or development of an organ habitually 

 suppressed; on the other hand, when phyllomorphy 

 occurs in sepals which usually are laminar in form 

 and nervation, the case is one of unusual growth or 

 hypertrophy, and not of the development of an organ 

 habitually suppressed, so that the amount of change 

 is greater in the former than in the latter instance. 



Under normal circumstances it will be found that 

 laminar venation is most common in gamosepalous 

 and vaginal venation in polysepalous calyces. And 

 the same holds good in cases where the calyx is ab- 

 normally leafy. The complete leaf development shows 

 itself more frequently among the monosepalous 



' This distinction between laminar and vaginal venation is well seen 

 in cases like Mtiaaaenda, Calycophyllum, or Dipterocarpus, where the en- 

 larged calycine segment has a strictly vaginal arrangement of its veins, 

 very diflferent from that which occurs in the true leaf-blades. These 

 are cases, therefore, where the sheath of the leaf is unusually enlarged, 

 and are not to be referred, as is often done, to metamorphosis of one or 

 more sepals to perfect leaves. Prolified roses, cherries, Ac, furnish 

 frequently parallel cases. With reference to M^issaenda, C. Morren held 

 the view that the petal-like sepal was really a bract adherent to the 

 calyx, and incorporating with itself one of the calycine lobes " soudee 

 au calice et ayant devoree, en englobant dans sa propre masse, un lobe 

 calicinal." The Belgian savant considers this somewhat improbable 

 explanation as supported by a case wherein there were five calyx lobes 

 of uniform size, and a detached feather-veined leaf proceeding from 

 the side of the ovary lower down (' Bull. Acad. Belg.,' xvii, p. 17, 

 Fuchsia, p. 169). 



