PHYLLODY OF THE FLOEAL WHORLS. 309 



teristic of the Plum, and Orchis has an innumerable qnantity 

 arising by repeated chorisis of the original placentary cords, 

 so in monstrous Primroses, etc., as represented in Fig. 88, 

 many additional ovular processes may be formed, not only on 

 the margins, but even, as stated, on the mid-ribs. 



One other point may be here noticed, d propos to the 

 following curious discovery by M, Baillon. I have regarded 

 a vascular cord as a " unit," as being capable of giving rise 

 to any appendage whatever ; and as long as it is in an axis 

 as a " trace," the cords of all organs are absolutely indistin- 

 guishable. Further, there is no difEerence between a cord 

 which will enter an appendage and one which will form a 

 pedicel from a peduncle. In the latter case, several cords 

 are usually required for the pedicel ; while one, the most 

 external of the " horseshoe " group given off at one side of 

 the peduncle (i.e. as seen in a transverse section), enters the 

 bract. In Erodium, cicutarium, which has three flowers to 

 the umbel with, very slender pedicels, one single cord is all 

 that the peduncle contributes to supply each of the pedicels, 

 and one very small cord for a bract. The cord for the pedicel 

 increases by radial chorisis, and so passes from the form of a 

 wedge to that of a fan, when the outermost parts increase 

 till they meet, aind so a circle is established. 



This shows that an "axis" and an "appendage" are 

 fundamentally due to the same kind of " unit." 



The reader will now see that in the following case * 

 the funicular cord, which is normally that of a foliar, i.e. 

 appendicular organ, supplied an axial cord ; just as many 

 leaves can give rise to buds which are often utilized for pro- 

 pagative purposes. 



* 8v/r le Diveloppement et la Germination des Grains Bulbifm-nves des 

 Ama/ryUid4es, par. M. Baillon, Bnll. Soo. de Fr., t. xxi., 30 (pub. en Sevue 

 des Oours Sci. Lyon, Aotit 30, 1873). 



