(428) 
made in Monotropa. Spiral vessels appear in the protoxy- 
lem of Sarcodes. Closed scalariform vessels only in the 
other genera. A medulla is present in Sarcodes and Pteros- 
pora, and secondary thickening occurs in these two genera, 
which gives the roots a stem-like appearance. The roots of 
these two plants probably live two or more years while the 
others are annuals. The roots are to be considered as the 
main axis in the Monotropaceae, since they serve to repro- 
duce the plant, as organs of storage, and as a habitat for the 
symbiotic fungus, which is the absorbing member in the asso- 
ciation. 
Literature to which Reference is Made. 
1. Chatin Ad. Anatomie comparée des végétaux. Plantes 
parasites. 1892. 
2. Fries, E. Systema mycologicum, 8: 440. 1832. 
3. Fries, E. Summa vegetabilum Scandanaviae. Sec. 
Post. 1849. 
. Kamienski. Die vegetative Organe der Monotropa 
flypopitys. Mem. d.1. Soc. Nat. et. Math. d. Cherbourg, 
884. 
5. MacDougul: Symbiotic Saprophytism. Annals of Bot- 
any, 13: March, 1899. 
6. Oliver. On Sarcodes sanguinea Torr. Annals of Bot- 
any, 4: 304. 1890. 
7. Rylands. On the’nature of the byssoid Substance found 
investing the Roots. of Monotropa Hypopitys. Phytologist, 
I: 341. 1842. 
8, Sarauw. Rodsymbiose og Mykorhizer. Bot. Tids- 
skrift, 18: Hft. 3 and 4. 18093. 
Explanation of Plates, 
All figures are of Afonotropa uniffora, unless otherwise stated. 
Fig. 1. Section of mass of roots at base of stem. 
Figs. 2 and 4. Origin of secondary roots. Fig. 4 shows the initial cells 
arising in the third cortical layer of the main root. Fig. 2 illustrates an ad- 
vanced stage of development of the new apex. ‘The young root has pushed 
beyond the general outline of the main root, and the outer cells of the root- 
cap have collapsed 
