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Proceedings of Boyal Society of Edinburgh. [sess. 
Fig. 26. Transverse section. Transition region between root and hypocotyl, 
showing {per. ) many layered interfascicular pericycle; and ext. c., small celled 
external conjunctive tissue investing the bundle ; end., endodermis ; cb ., 
cimbium. 
Fig. 27. Transverse section. Cotyledon trace at base of young hypocotyl, 
showing ext. c., external conjunctive, forming cap to inside of bundle, and all 
there is to represent the perimedullary zone of Flot ; end., endodermis ; per., 
pericycle ; P., phloem ; X., xylem ; cb., cambium ; /., fascicular pericycle cell, 
which will become a fibre. 
Fig. 28. Longitudinal radial section through interfascicular region of hypo- 
cotyl, showing endodermis with starch {end.), and a pericycle {per.), consist- 
ing of a single layer of elongated cells ; cor., cortex. 
Fig. 29. Longitudinal radial section passing through the protoxylem {p.x.) 
of a cotyledon trace; ext. c., four layers of elongated external conjunctive 
cells, which form the investing cap of transverse section, and represent peri- 
medullary zone. 
Fig. 30. Transverse section, epicotyl. The leaf traces are here so closely 
packed as to bring their external conjunctive investments into lateral contact, 
and to form a perimedullary zone ; a., a large cell of the pith forcing itself 
between the protoxylems of two adjacent leaf traces almost continuous 
sheath of pericycle fibres. 
