310 BOTANICAL GAZETTE [NOVEMBER 
structures that may be rudimentary or wanting in others. Such 
structural and anatomical diversity either becomes more marked, 
or is entirely lost in hypertrophied or atrophied organs. 
The deformations and anatomical changes resulting i in the 
hypertrophied branches of A. fectinata, affected with . elatinum, 
were first described in a general way by De Bary* who demon- 
strated that the “witch broom” was caused by a fungus. 
Later, Hartmann? made a comparative anatomical study of the 
diseased and the healthy leaves and branches of the same witch 
broom. The writer3 has made a comparative study of the dis- 
eased and the healthy buds of A. fectinata, as well as the forma- 
tion and distribution of the abnormal resin canals that are formed 
in the wood of the branches affected with the same fungus. By 
comparing the witch broom of A. firma Siebold of Japan with 
that of A. pectinata, it was found that ditferences occur in the two, 
depending largely upon the differences existing in the normal 
leaves and branches of the two mountain species of Abies. 
According to the analyses of Mayr,‘ the wood of A. pectinata 
contains the least per cent. of resin of any of the cultivated firs. 
A. balsamea differs from A. pectinata and A. firma, not only in its 
specific characters and peculiarities, as a large resin or balsam 
producer, but also in being aswamp species. For this reason, as 
well as its being exclusively an American species, one would 
expect to find marked structural and anatomical changes in the 
affected leaves and branches. The anatomy of the @. elatinum 
witch broom of A. balsamea has not been studied. 
For the purpose of making a comparative anatomical study 
of this witch broom, material was collected from trees growing 
in a bog near Walker, on Leech lake, northern Minnesota, Sep- 
tember 1896. 
*DE Bary: Ueberden bs und die H b ler Weisstanne. Bot. Zeit. ries 
7 HARTMANN, F: Anatomische Vergleich der Hexenbesen der Weisstanne m! 
den normalen Sprossen derselben. Inaug. Diss. Univ. Freib. 1 
3Ueber abnorme Bildung von Harzbehiltern und an 
— brecaraimconsa in Holze erkrankter Coniferen. Inaug- Diss. 
Miinchen, 
ee. Herwricn: Durability of resinous woods. ei Sci. Monthly 28: 
Diss. Univ. 
1892. oe 
dere zugleich auftretende on 
