Leaf and Sporocarp in Marsilia quadrifolia , L. 
H3 
EXPLANATION OF FIGURES IN PLATES 
X, XI, AND XII. 
Illustrating Dr. Johnson’s paper on the Development of Marsilia quadrifolia. 
Abbreviations used : — A., direction of the apex ; a. b., axial bundle of the petiole ; 
a. c., air-canal ; arc., archesporium ; a. s. w., acroscopic segment wall ; B., direction 
of base ; b. c. tc ., basal cell of the trichome ; b. m. c., basiscopic marginal cell ; br ., 
branch (axial bud) ; b. r. , rod of brown-walled cells ; b.s., bundle-sheath ; b.s.w., 
basiscopic segment-wall ; b. w., basal wall of the capsule ; c., capsule ; c.p., trans- 
verse partition; c.p.c ., transverse partition-cell; c.p.p ., spores in transverse 
partition; /)., dorsal side; d., dermatogen; d 1 ., d 2 ., &c. dermatogen of sections 
I, II, &c. ; d.b., dorsal bundle of sporocarp ; d. w., dermatogen-wall ; ep ., epidermis ; 
F., sporocarp ; F K, first sporocarp ; F 2 ., second sporocarp ; F. m. c., mother-cell 
of sporocarp ; g. r ., gelatinous ring ; h. a ., halving anticline of section I ; hy., hypo- 
dermis ; ind ., indusium ; i. ind ., inner layer of indusium ; i. s., intercellular space ; 
i.s. c., inter-soral cavity ; L., leaf ; l.a., first longitudinal anticline in plerome of 
section V ; /. b., lateral branch of dorsal bundle ; l. b.f, fork of the lateral branch ; 
l.p., longitudinal partition; l.p.c., longitudinal partition cell; l.p.p., pores in 
longitudinal partition ; /. t ., lower tooth ; ma-sp., macrosporangium ; ma-sp. m. c., 
macrosporangium m other- cel 1 ; m.c., marginal cell; m. c 1 ., in. c. 2 , &c., marginal 
cell of the first, second, &c. grade; mi-sp ., microsporangium ; mi-sp. m. c., micro- 
sporangium mother-cell ; mp., mesophyll ; m. w., median wall ; 0 , hy., outer layer 
of hypodermis of capsule; o.ind., outer layer of indusium; p 1 ., lower pinna; 
p 2 ., upper pinna ; pa., placenta ; pa. b., placental bundle ; pa. br., placental branch ; 
pb 1 ., periblem of section I; pb 2 ., periblem of section II; pb., periblem ; p.c ., 
partition-cell ; pi., plerome ; pi 1 ., plerome of section I ; pi 2 ., plerome of 
section II ; pi. w., plerome-wall ; p. ma-sp. me., primary macrosporangium mother- 
cell; S ., stem ; sc., soral cavity ; st., stalk ; st. b., stalk-bundle ; st. c„ stalk-cell of 
microsporangium ; s. w., segment-wall; ta 1 ., to 2 ., &c. first, second, &c. transverse 
anticlines of marginal cell ; tc., trichome ; tp., tapetum ; tr., trachea ; t. s., tannin- 
reservoir; u. t ., upper tooth; V., ventral side; X., apical cell; I. II. Ill, & c. 
first, second, &c. section-walls ; 1. 2. 3., &c. first, second, &c. segments of the 
apical cell on one side. 
All figures are camera drawings, and all are from microtome-sections, except 
Figs. 25, 31% and 44. 
PLATE X. 
Fig. 1. Transverse section of stem through apical cell of young leaf, x 300. 
Fig. 2. Sagittal section of a leaf nearly at the end of apical growth, x 200. 
Fig. 3. Part of a sagittal section of the petiole of an older leaf, x 300. 
Fig. 4. Ventral surface of tip of a young leaf, x 400. 
