AND AFFINITIES OF STEPHANOSPERMUM. 397 
to the level of the septum or diaphragm (d.) or even lower into the supra-archegonial gap. 
pr, prothallium with a well-marked archegonium (ar.); p.g., an abortive pollen-grain 
trapped in the nucellar canal; co., the collar (cf. fig. 14), a persistent detached portion 
of the epidermis ; cc, ill- preserved remains of displaced endotesta ; e., epidermis of nucellus, 
x30. S2. (Seep. 371.) 
Fig. 4. Transverse section of the sclerotesta. p., the palisade-layer showing the filamentous and 
often spiral contents with lenticular enlargements at places (cf. P1. 43. figs. 22, 23, & 24) ; 
f. longitudinally running fibrous layer; et., epithelioid lining of the sclerotesta; n.e., ill- 
preserved epidermis of the nucellus. The intermediate endotesta between e£. and n.e. not 
shown. x145. S17c. (See p. 364.) 
Fig. 5. A somewhat tangential longitudinal section of the apex of aseed. Wall of pollen-chamber and 
sclerotesta badly preserved. Supra-archegonial gap and septum well shown. The strands 
within the crown (A.) are excellently shown. x17. Sla. (Sce p. 365.) 
Fig. 6. Median longitudinal section through the micropyle. et., epithelioid lining of sclerotesta. The 
nucellar beak is not preserved, but two fragments of the collar are preserved to right of 
apex of nucellus. Within the pollen-chamber, three large normal pollen-grains and one 
abortive. The grain p. is much enlarged in Pl. 44. figs. 32, 33, & 34. x14. S84. 
(See p. 371.) 
. Median longitudinal section through the base of the seed represented in fig. 6. The entering 
bundle and tracheal disc are well shown, as are the general relations of the parts at the base 
of the seed. a, point at which the macrospore has separated from the wall of nucellus. 
The chalaza is represented in detail in Pl. 48. fig. 21. x15. S8». (See p. 367.) 
Fig. 9. Tangential section through corner of supra-archegonial gap, showing the tracheides passing into 
the space. The section follows the plane running obliquely down from a in fig. 10. A group 
of these tracheides is drawn much enlarged in Pl. 43. fig. 28. m.w., macrospore-wall ; ep., 
epidermis of nucellus. x80. S 9c. (See p. 369.) 
Fig. 
“I 
PLATE 42. 
Fig. 8. Left-hand corner supra-archegonial gap—from the same specimen as fig. 10, but with the angle 
here directed upwards. Shows the tracheal sheath (£r.) splitting into an upper layer (¢r.’) 
lining the side of the gap, and a lower layer (/r.*) resting on the macrospore-wall (m.w.). 
n.e., epidermis of nucellus. x155. S 12. (See p. 369.) 
Fig. 10. Tangential section through apex of seed. Shows strands on the summit. The epithelioid 
lining of the sclerotesta is admirably preserved. Of the pollen-chamber only the flanking 
tissue (shoulder) is shown. The supra-archegonial space is conspicuous. a to left-hand 
bottom corner, plane of section from which fig. 9 was taken. x14. $12. (See p.369.) 
Fig. 11. Longitudinal section of lower portions of shoulder from same section as fig. 2. ah. tissue 
of shoulder; p.c., corner of pollen-chamber ; s., septum (i. e., remains of floor of pollen- 
chamber) ; s.a.g., supra-archegonial gap; ¢r., tracheides attached to the septum, also drawn- 
out spirals lying free in the gap. x105. S74. (See p. 369.) 
Fig. 12. Longitudinal section very similar to fig. 10. The supra-archegonial gap has numerous 
drawn-out tracheides in the angle, admirably shown (ri. x30. S7». (See p. 369.) 
Fig. 13. Longitudinal section of apex of nucellus of a rather younger seed than those usually found. 
end.t., endotesta; s.t., sclerotesta ; p.c. the quite small pollen-chamber ; s.a.g., supra- 
archegonial gap—in this case developed by a splitting of the tissue immediately below 
the tracheal sheath, x x mark the region of splitting; e.t., displaced cell belonging to the 
epithelial lining of sclerotesta; fr. the tracheal zone; ar., archegonium. X 30. S34. 
(See p. 370.) 
