GROUPS OF TISSUES, OR TISSUE-SYSTEMS. 41 
corn the central portion is composed of tracheary tissue, 
consisting of pitted, spiral, ringed, and reticulated vessels 
Fira. 25.—Transverse section of fibro-vascular bundle of Indian corn. a, side 
of bundle looking toward the circumference of the stem; 2, side’of bundle look- 
ing toward the centre of the stem; g, g, large pitted vessels; s, spiral vessel; 1, 
ring of an annular vessel; J. air-cavity formed by the breaking apart of the sur- 
rounding cells; ¥, v, latticed cells, or soft bast, a form of sieve-tissue. Magnified 
550 times. 
(Fig. 25, g, 9, 8 7, and the tissue between v—s, g—g). 
Lying by the side of the tracheary tissue (on its outer side 
