THE HIGHER CRYPTOGAMIA. 313 



rounds the young undeveloped frond of Ophioglossum is 

 not entirely closed. On that side of it which is turned to- 

 wards the next older frond (which has broken out of its 

 covering) it exhibits a narrow opening surrounded by a 

 tuft of jointed hairs constituting in this plant the only 

 appendicular organs of the epidermis (PI. XLI, fig. I). On 

 the inside also the hollow space which covers the oldest of 

 the enveloped fronds is not closed. A narrow cylindrical 

 passage leads from its fore-side into the cavity which en- 

 closes the next younger frond, and from this in like manner 

 into the cavity in which the frond destined for development 

 in the third following year is produced ; and lastly the 

 latter is in open communication with the narrow space 

 above the flat end of the stem (PI. XLI, figs. 1, 2). 



The fronds surround the end of the stem in a | left 

 handed spiral, as may be clearly seen in transverse sections 

 of the stem at the place where the vascular bundle which 

 passes from the cylinder of vascular bundles obliquely up- 

 wards to the fronds, traverses the cortical parenchyma 

 (PL XLI, figs. 3, 3*). The young frond makes its appear- 

 ance near the depressed, almost flat end of the stem, in the 

 form of a slender conical knob, from the fore side of which 

 a fleshy flat stipule-like excrescence, as in Marattia, is pro- 

 duced (PL XLI, fig. 2 h ). This cellular mass developes in 

 breadth more vigorously than the part of the frond which 

 is situated above its place of attachment. It embraces 

 about two fifths, and the frond about one third, of the zone 

 of the stem upon which they both stand. The axile stipule 

 attaches itself by its fore edge to the front surface of the 

 stipule of the obliquely-opposed next older frond and at 

 its lateral edges it amalgamates immediately with the 

 stipules of the adjoining older fronds to the right and left,* 

 which stipules have already amalgamated inter se, and pro- 

 trude considerably beyond the youngest frond behind which 

 they stand. By this means the hollow space is formed 

 which encloses the young frond. The walls of the cavity 

 are derived from four different sources. The wall which is 

 turned towards the front surface of the enclosed frond con- 



* The second and third, reckoned backwards from the frond of which we 

 are speaking. 



