1898 } THE LEAF AND SPOROCARP OF PILULARIA 23 
PRANTL, K., ’81; Untersuchungen zur Morphologie der Gefisskrypto- 
gamen, Heft II, Die Schizaeaceen. 1881. 
ussow, E., ’72: Vergleichende Untersuchungen d. Leitbiindelkrypto- 
gamen. Mém. ieee: imp. de St. Petersbourg rg: —. 1872. 
SADEBECK, R., ’74: Uber die Entwickelung des Faieibantes 1874. 
EXPLANATION OF PLATES I-III. 
Abbreviations used.— A, apex ; ad, axial bundle; ac, air-canal; arc, 
archesporium ; 44, basal pit; ds, bundle sheath; dw, basal wall; cp, trans- 
verse partition ; D, dorsal; d, protoderm ; dw, protoderm-wall; ¢, epider- 
; #, sporocarp ; Aa, halving anticline ; Ay, hypodermis; Ay*, outer hypo- 
dean. hy, inner hypodermis ; zd, indusium ; zsc, intersoral cavity ; Z, leaf; 
4b, lateral branch of vascular bundle; 4bf, fork of the lateral branch; J, 
light line; &, longitudinal partition; 74, lower tooth; mc, marginal cell; 
mic*, mc*, etc., marginal cell of the first, second, etc., grade ; mp, mesophyll ; 
mw, median wall; fa, placenta; fad, placental bundle; faér, placental 
branch; #4, ground-meristem; fc, partition cell; A/, procambium; A/w, 
procambium-wall ; #%, pores in partition; S, stem; sc, soral cavity; sc/, 
Stereome bundle; sf, sporangium; sfc, sporangial cells; s¢, stoma; sw, 
segment wall; /a', first transverse anticline; ¢c, trichome; ¢/, tapetum ; 7/7, 
trachea; X, apical cell; I, Il, etc., first, second, etc., section walls. 
All figures are camera drawings from microtome sections, except figures 
36-38, which are copied from Meunier. 
PLATE f, 
Fig. x. Transverse section of stem through apical cells of two young 
leaves. & 400. 
Fic. 2. Ventral surface of tip of young leaf. x 400. 
FiG. 3. Lateral surface of same. X 400. 
Fic. 4. Part of transverse section of young leaf. x 400. 
FG, 5. Similar section of an older leaf. X 400 
Fig. 6. The same stil] older. X 400 
Fig. 7. The same older than the last. X 400. 
Fig. 8. The same still older than the last. X 400. 
Fig. 9. Similar section of nearly mature leaf. x 75. 
Fig. 10. Part of tangential section of a young leaf through the partitions 
and air-canals, x 200. 
IG. 11, Similar section of older leaf. X 200. 
Fig. 12. Part of transverse section of stem showing ventral surface of a 
young leaf and the mother cell of a sporocarp. X 400. 
‘IG. 13. Dorsal surface of tip of a young sporocarp. X 400. 
Fic. 14. Ventral and lateral surface of the same. X 400. 
