Page 07 – Longitudinal sections of the stem of an 8-months-old seedling

Title

Page 07 – Longitudinal sections of the stem of an 8-months-old seedling

Creator

Date

c. 1940

Format

Description

Fig. 9 (following)

Series of longitudinal sections (tagential, A, C, D and F; and radial, B and E) of the stem of an 8-months-old seedling to show the development of the axis at different levels. A, B, and C, X25; D, E and F, portions of A, B, and C, respectively, enlarged. X50.

pm, promeristematic "cap" in apical growing region (a); l, youngest leaf primordium; l₁, l₂, l₃, etc., successively older leaf primordia and young leaves; sm, region of specialized meritstematic tissue where roots are formed (none present in these views); r, root at lower level; vn, vascular network, at boundary between cortex (c) and stele (s); lg, leaf gap in vascular network, through which leaf trace (lt) passes; bb, bundles enter leaves from stem; ps procambial strand for youngest leaf primordium (l); ps₁, for second youngest primordium, l₁; ra, raphides.