On “ Fasciation." 73 
garden specimens may affect the whole of the lateral branch- 
system of the plant. Similar phenomena, but in a less perfect 
manner, may he noticed in such allied forms as H. rigidus and H. 
strumosus, in their garden varieties. In such cases the dichotomy 
may occur (I.) in the foliage region, giving long-stalked pairs of 
capitula; (II.) close behind the involucral region, giving twin- 
heads; (III.) within the involucre, resulting in the phenomenon 
of ‘ two-eyed’ capitula, with a more or less perfect ray series between 
the two disks.” I have myself observed this dichotomy of the 
third type in Helianthus. 
When the equilibrium of the organism is upset from whatever 
cause there is often a natural tendency for it to revert in some 
of its characters to an ancestral condition. I myself am inclined 
to regard these cases of pleotomy and dichotomy, giving rise to the 
“ fasciated ” condition, as reversions to an ancient type of 
branching, a type which probably represents the line of least 
resistance for an organism when impelled, under powerful stimulus, 
to reproduce itself by the most rapid method possible. Just as in 
the cases of multiple personality, the “ obsessing memories,” latent 
in the sub-conscious mind under ordinary conditions, may, under 
the influence of certain stimuli, cause the organism as a whole to 
live in and focus its attention upon some past and long-forgotten 
condition ; in the same way our higher flowering-plants very often 
lose their balance and live in the long-past branching conditions of 
Lycopods, Ferns and Algae. In these latter cases, the branching is 
probably always primarily in one plane ; 1 and is precisely the same 
phenomenon as the linear series of buds or branches at the apex of 
all fasciated shoots; and if we can imagine the successive 
dichotomies in their shoots to take place with extreme irregularity, 
inequality and lack of symmetry, we should probably obtain an 
ordinary “ fasciation ” such as occurs so often as an abnormality in 
the shoots of our Angiosperms. The leaves of the Ginkgoaceae 
are interesting for comparison in this connection. In Ginkgo biloba 
the dichotomy of the leaf has proceeded but a short way in the 
ordinary form ; but other varieties reveal a much deeper primary, 
and the occurrence of secondary dichotomies. In the fossil 
form Baiera gracilis , the entire leaf is deeply divided up into 
narrow linear segments, like the leaf in the ferns Actinopteris 
radiata, and Schizcea dichotoma. The whole of such cases whether 
they occur in shoots or leaves, represent the phenomenon of normal, 
stereotyped and symmetrical “ fasciation.” 
As to the third or physiological sub-division of the etiology 
1 Cf. Dictyotaceae. 
