BHYTHM. 221 



I. The dadode form, in which the shoot becomes secondarily 

 flattened in one plane, by a more rapid growth in that 

 direction than in any other (cf. Opuntia). 

 II. The fasciafed stem, usually though not necessarily classed 

 as a monstrosity. 



III. The so-called dorsiventral shoot, in which centric growth is 

 replaced by an eccentric distribution which involves the 

 phyllotaxis system. 



In the first of these cases (Opuntia), section of the apex (fig. 81) 

 shows that the original phyllotaxis pattern is normal, and only 

 becomes distorted at a subsequent stage. 



In the "fasciated" system, the centric distribution around a 

 point (the single growth-centre) is changed for an attempt at 

 similar distribution around a number of such centres (cf. monstrous 

 flowers of Buttercups with two or three distinct gynoeeial cones, 

 and double Daffodils) or around a longer or shorter series of such 

 points constituting a line, with the result that great disturbances 

 ensue, owing to the impossibility of normal uniform growth ex- 

 pansion in such a system ; the resultant paths of which would, 

 along the flanks of the crested apex, be represented by parallel 

 straight lines replacing the intersecting curves, which would still 

 appear at the ends of the system. These appearances are well 

 shown in the case of a fasciated shoot of Oenothera (fig. 82) ; the 

 whole of the curved crested apex, over an inch in length, could 

 not be cut in one transverse plane, but a small portion suffices to 

 show the marked irregularities produced both in shape and series 

 of the foliage-leaves as their growth expansion brings them into 

 new and anomalous contacts. 



The case of the change from centric distribution to eccentric, 

 the so-called dorsiventral shoot, may be left for subsequent dis- 

 cussion; it is only necessary so far to point out that the con- 

 struction lines of its phyllotaxis system should continue to be 

 represented by orthogonal trajectory curves, just as those of the 

 eccentric starch-grain apparently follow the same laws as those 

 presented by centric forms. 



In such a circular growth diagram, again, the result of a uniform 

 rate of growth in the whole system may be expressed by a 



