212 T. Holm — North American Terrestrial Orchidece. 



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EXPLANATION OF FIGUEES. 



Figure 1. — Transverse section of the root of Habenaria repens, showing a 

 part of the central-cylinder ; End. = endodermis ; P. = pericainbium ; P. L. 

 = proto-leptome ; £T=hadrome. x 320. 



Figure 2. — Part of stolon with bud and roots of Platanthera dilatata, 

 magnified, b — apex of the bud ; r 1 and r 2 = young roots ; r = the tuberous 

 root ; st. = base of stolon. The dotted lines indicate the places where the 

 sections have been laid. 



Figure 3. — Transverse section of one of the two small mestome-cylinders 

 of the stolon ; letters as above, x 320. 



Figure 4. — Transverse section of a mestome-cylinder from the tuberous 

 root ; letters as above, x 320. (Figs. 3 and 4 are both of Platanthera dila- 

 tata ; fig. 3 of a specimen from Vermont, fig. 4 of a specimen from Mt. 

 Elbert in Colorado.) 



