Ana tony of the Genus Selaginella , Spr. 33 
whilst on the other, its wonderful adaptations for cross-fertilization, bringing 
into play the most elaborate mechanism seen in the Pteridophyte group, 
and its near approach to the seed habit, render it one of the most interest¬ 
ing as well as instructive genera in the whole of the plant world. 
EXPLANATION OF PLATES III AND IV. 
Illustrating Miss Mitchell’s Paper on the Strobilus of Selaginella. 
PLATE III. 
Fig. 1. T.S. megasporangium of S. spinosa. a. hinge cells in section ; b. thickened edge ot 
valve ; c. tract of shallow tissue giving flexibility ; d. inner sporangium wall. 
Fig. 2. L.S. megasporangium of S. spinosa ; lettering as in Fig. i. 
Fig. 3. Opening sporangium of S. spinosa. 
Fig. 4. Valve of megasporangium of S. spinosa. sp. position of spore; a. transversely 
orientated cells ; c, c'. cracks ; b. thickened edge of valve. 
Fig. 5. L.S. ligule of S. inaequalifolia. gloss, glossopodium ; g.sk. glossopodial sheath; Ir.sh. 
tracheal sheath. 
PLATE IV. 
Fig. 1. .S’. Lyallii , ‘ ligular’ sporangium, st. sporangium stalk; gloss, glossopodium. 
Fig. 2. S. Lyallii , two sporangium subtended by one leaf. 
Fig. 3. T.S. stele of cone of S. Lyallii. pcy. pericycle; end. endodermis; phi. par. phloem 
parenchyma; s.t. sieve-tubes ; p.ph. protophloem. 
Fig. 4. ‘ Hinge ’ region of S. helvetica. 
Fig. 5. Fusion of bundles in cone of S. inaequalifolia. 
Fig. 6. Valve of microsporangium, S. Kraussiana. a. thickened band of tissue. 
Fig. 7. Valve of microsporangium, S. helvetica. 
Fig. 8. Diagram showing fusion of bundles in cone of S. Lyallii. 
Fig. 9. T.S, stele of cone of S. spinosa. 
Fig. 10. L.S. microsporangium of S. helvetica. 
Fig. 11. A. oregana , branched cone. a. well developed sporangia; b. imperfect sporangia; 
c. entirely aborted sporangia ; d. dehisced sporangia; e. young sporangia. 
Fig. 12. S. Kraussiana , abortive microsporangium. 
Fig. 13. L.S. ligule of A. IVildenowii. 
Fig. 14. Cone showing reversion to vegetative characters, S. sp. 
D 
