5°4 
May brook . — On the Haustoria of 
the host root h.r. is a single strand of tracheidal elements tx . This strand 
may be one, two, or three cells in thickness when cut in this plane, but is 
rarely more, and most often consists of a single row of cells. Fig. 3, B, shows 
a portion of the same haustorium in detail ; the relative sizes of the cells nx. 
Fig. 3. A. Diagrammatic median longitudinal section of haustorium in a plane of a longitudinal 
section of the mother root and transverse section of host root, x 57^. B. Detailed drawing 
of a portion of haustorium represented in A. x 223^. C. Diagrammatic obliquely longitudinal 
section of root of Pedicularis attacked by two haustoria, h 1 and I12 , and bearing two haustoria, h 3 
and h 4, which are attacking roots of Calluna , c 1 and c 2. x 44. D. Portion of haustorium, h 1 in 
detail, x 223^. t p. — tracheidal plate; tx. = tracheidal connexion; nx. = cells of ‘nucleus’; 
.— cortex of haustorium ; v.s. = vascular strand of parasitic root ; h.r. = host root ; p.t. = penetrat- 
ing tracheides; d.r. = dead remains of host root; xy. = xylem of host root. 
