UPel Bf AMIRI UE FOI AECD-3446(App.) 21 x 2p, Riehahicapry sag URE AS IMEY ARATANT aie SREY be MTR TAY5HPDEAEL er SETI 04 a . * duct; B, secretory cell; parenchyma; D, external Fig. 7—- Photomicrograph of normal growing tip. (x 145). A, young leaf; B, tunica; and C, corpus. ‘ UNIVERS*=" ® * ery. OF PeSeae oS; a SeeORES ORS phloem; E, cambium; F, xylem; and G, internal phloem. = CERESAM SipaREAUMAROeIT,rae ee mmm Fig. 6— Photomicrograph of segment of a cross section of the normal stem of [Ipomoea tuba. (x 175). A, lacteriferous | TOT eernatantieRMIT: