Plant Impressions or Incrustations . 385 
investigated the cuticle of the rachis of Mariopteris muricata , and dis¬ 
covered structures which he concluded were the bases of epidermal 
emergences. 
Some time later I obtained material of Mariopteris , cf. muricata , 
Schloth., and made some transfer preparations. The under surface was 
found to be regularly studded with capitate glandular hairs 1 (PI. IX, 
Fig. 2, /z, and Fig. 5). These glands occurred also on the veins and 
revolute margins of the pinnules. Portions of the pinnules which became 
loosened in the etching process were used to make cuticle prepara¬ 
tions by Schulze’s method. 2 I found that the cuticles of the upper and 
under surfaces were easily separable. The upper cuticle (PI. IX, Fig. 3) 
was apparently identical with that figured by Huth, 3 and showed structures 
(PI. IX, Fig. 3, /z., hi) which corresponded exactly to the ‘ Atemporen ’ in 
form and number. The lower cuticle (PI. IX, Fig. 4) was of quite a different 
nature: it was much thinner than the upper, and showed the outlines of the 
epidermal cells only very faintly. Glandular hairs were frequent, and occa¬ 
sionally I found the cuticularized portions of the supporting cells of a hair, 
which corresponded so closely with the structures seen on the upper cuticle 
as to leave no doubt of their similar nature. There was one very interesting 
fact observed which throws light on the nature of these glands. In many 
instances numbers of microspores of various types were found attached to 
the stalks of the glands and to the epidermal cells surrounding them. 
These spores were not loosened even by prolonged treatment in Schulze’s 
macerating fluid. They were also found scattered in large numbers over 
the surfaces of the prepared cuticles (PI. IX, Figs. 3, 3 a, and 5). There 
were few spores in the matrix surrounding the plant, as could be verified by 
examination of the transfer preparations, for any spores lying in the bedding 
plane of the frond would have remained fixed to the balsam. We may 
therefore conclude with considerable confidence that the spores were 
sticking to the plant when it fell into the lake or river in the bed of which 
it was subsequently silted up, and that the glands secreted some sticky 
substance during the life of the plant. 
In addition to these glandular structures, groups of two to six small 
papillae occurred at frequent regular intervals over the surface of the cuticle 
of the abaxial surface in areas which corresponded to the spaces between 
the veins (PI. IX, Fig. 3). The papillae in these groups surrounded 
a small area which in some examples was occupied by a small stoma of 
quite the usual type, consisting of two curved guard cells surrounding 
a narrow elliptical pore (PI. IX, Fig. 6). The whole structure was very 
much smaller than the hair-bases. The papillae may almost certainly be 
1 Cf. glands of Lagenostoma loinaxi. Oliver and Scott (1904), PI. VI, Figs. 20 , 21 , and 
PI. VIII, Figs. 17 , 18 . 
2 Schulze, F. (1855). 
3 Huth, W. ( 1913 ). 
