636 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
PHOTOGRAPH 17.—Transverse section of the young stem of 2. rhomboideus. The 
internal phloeoterma is still visible. (X. 25). 
PHOTOGRAPH 18.—Transverse section of the young stem of 2. rhombotdeus, showing 
the communication of internal and external phloeotermal sheaths 
through the foliar lacuna. (X. 25.) 
PLATE X. 
PHOTOGRAPH 19.—Transverse section of the young stem of Avzemone pennsylvanica, 
showing the presence of an internal phlceoterma. (X. 25.) 
PHOTOGRAPH 20.—Transverse section of the older young stem of 4. fennsylvanica, 
showing the overlapping of the foliar gap. (X 25.) 
PHOTOGRAPH 21.—Transverse section of the young stem of Brasenia purpurea, showing ; 
the primitively tubular condition of the stelar system. (X. 20.) 
PHOTOGRAPH 22.—Transverse section or the young stem of Muphar luteum, var. 
Kalmiannm, showing the tubular stele. (X 25.) 
PHOTOGRAPH 23.—Transverse section of the older young stem of Mufphar advena. 
(X 25.) 
PHOTOGRAPH 24.—Transverse section of the young epicotyledonary stelar system of 
Nelumbium luteum; a, primitive stelar strands; /, cortical } 
bundles. (X 25.) 
PLATE XI. 
PHOTOGRAPH 25.—Central cylinder of Parnassia palustris. (X 45.) 
PHOTOGRAPH 26.—‘‘ Polystelic ”’ phase of central cylinder of P. palustris, 2’ and 7? are 
leaf traces. (X 12.) 
PHOTOGRAPH 27.—Inferior region of ‘‘astelic’ 
palustris. (X 45.) 
portion of central cylinder of P. 
PHOTOGRAPH 28.—Transverse section of the stele of P. palustris, at point of origin of a 
leaf-trace (X 12.) 
PHOTOGRAPH 29.—Transverse section of ‘‘ astelic’”’ central cylinder of P. parvifiora, 
g and 2? are foliar gaps; /is a leaf-trace. (X 25.) 
PHOTOGRAPH 30.—Transverse section of central cylinder of the young stem of Hepazica 
triloba. (X 40.) 
