56 STRUCTURE AND LIFE-HISTORY OF HAY-SCENTED FERN. 



PLATE 22: 



238. Transverse section of protostele below first leaf-gap. X 210. 



239. Transverse section o stem through the first leaf-gap, o. No inner phloem. 



Siphonostelic structure occurs o.i mm. higher up; tr, region of first leaf- 

 trace. X 210. 



240. Transverse section of siphonostele between first and second leaves. 



241. Transverse section of siphonostele midway between third and fourth leaves. 

 242-245. Serial transverse sections of the center of the stele at the origin of the 



inner endodermis. 241 to 242 is 60 /*; 242 to 243 is 10 /a; 243 to 244 is 

 20 /A; 244 to 545 is 70 p. All between third and fourth leaves. X 210. 

 PLATE 23: 



246. Sagittal section of young fern attached to prothallus; ;;?, stem-initial; o, calyptra 



r, root; /r, first leaf; u, prothallus. X 75. 



247. Detail of transition from root to stem, from same series as fig. 246; ;;/, anterior; 



r, posterior; u, upper part. 



248. Slightly oblique transverse section of petiole of third leaf of sporeling; d> upper 



side. X2io. 



249. Glandular hair from leaf of adult plant. X 43. 



250. Transverse section of petiole of first leaf, showing sectioning of marginal cells. 



Endodermis dotted; m, marginal cell. X 360. 



251. Sinus of leaf-margin of seedling; dotted cells are epidermal. Surface view of 



cleared specimen. X 350. 



252. Young rhizoids and tips of mature ones from root of three-leaved sporeling of 



fig. 267. X 350. 



253. Optical section of spongy parenchyma of first leaf of sporeling; cleared in gly- 



cerine. X 350. 



254. Epidermis and developing stomata on sporeling leaf; m, stoma mother-cells. 



X43- 

 PLATE 24: 



255. Horizontal section of calyptra (11} and embryo through root and rudiment of 



first leaf (tr}. X 360. 



256. Diagrammatic cross-section of sporeling plant through third leaf-gap; tr, petiole 



0, leaf-gap. 



257. Diagrammatic cross-section of stele and starchy cortex of sporeling stem at 



fourth leaf-gap; o, leaf-gap. X 75. 



258. Hairs of third leaf of sporeling No. 3; b, acicular; ;;z, moniliform ; n, glandular. 



X 350. 



259. First leaf of sporeling No. 2. X 5. 



260. Second leaf of same plant. X 5. 



261. Second leaf of plant No. 3. X 5. 



262. Third leaf of plant No. 3. X 5. 



263. Third leaf of another plant. X 5. 



264. Fourth leaf of plant No. 3. X 5. 



265. Fourth leaf of plant No. 4. X 5. 



PLATE 25: 



266. Lower epidermis of first leaf of sporeling. X 350. 



267. Three-leaved sporeling (No. i) with portion of prothallus () still attached. 



1, 2, 3, first, second, and third leaves. 



268. Surface view of petiole of second leaf of sporeling (No. i), with stoma. 



269. Sporeling stem with roots and leaves cut off. Drawn from nature by Miss M. 



E. Rogers. 



270. Forked stem of seedling, i, primary root leading up to the original simple 



stem. Drawn from nature by Miss M. E. Rogers. 



