150 
J antes Small 
In the Calenduleae the antipodals are more or less normal but 
a special micropylar haustorium is developed. 
The development of the haustorium in the Chrysanthemidinse 
closely approximates to that in Senecio. 
Although the data in the Inuleae are very meagre, what there 
is tends to support the diphyletic development of that tribe, the 
Inulinae being near the Senecioninae and leading to the Centaureinae 
through the Buphthalminae. 
In the Centaureinae the slight development of the haustorium is 
rather surprising considering the advanced position of the tribe, 
but is, nevertheless, quite in keeping with the slight development of 
the haustorium in the ancestral Buphthalminae. 
The haustorium in the Astereae is slightly developed in the 
primitive Homochrominae, more developed in the more advanced 
Bellidinae and Conyzinae, and most developed in tbe advanced 
Heterochrominae. An investigation of the antipodals of the 
Eupatorieae should prove interesting in view of the derivation of 
that tribe from the Heterochrominae. 
The coenocytic tube type of haustorium is best developed in 
the Heliantheae. The structure of the organ in the primitive 
Verbesininae is sometimes quite simple and in most, if not all cases, 
it is less developed than it is in the Coreopsidinae, especially Cosmos. 
The haustorium in the Zinniinae is simple, in the Melampodiinas it 
is more developed (cp. Fig. 79). 
The development, as far as it is known, in the Helenieae agrees 
with the origin of that tribe from the Senecioneae directly and not 
indirectly via the Heliantheae. 
In spite of the very restricted number of species in which the 
antipodal development is known, it is clear from the above that the 
data are drawn from sufficiently representative genera to furnish 
some interesting confirmation of previous phyletic suggestions. 
Chromosomes. Meek’s theory (76) of a constant diameter for 
the chromosome with a gradual elongation of each chromosome 
during evolution,and conjugation of the chromatin units in fours when 
the length-limit has been reached to give chromosomes with twice 
the original diameter, has been criticised by Farmer and Digby (54), 
who agree, however, that although the chromosome width cannot 
be strictly correlated with the evolutionary sequence, many of the 
lower animals and plants have smaller and narrower chromosomes, 
as compared with those of higher forms. The chromosome width 
varies so much in plants that it is certainly not very useful in 
dealing with phylesis within a family. 
Apart however from these considerations, the variation in the 
