Bower.—-Studies in the Phytogeny of the Filicales. 501 
simple hairs ; but later the distal cells elongate and become brown and 
indurated, while the proximal cells remain short and thin-walled, and 
divide by longitudinal walls, so as to form a considerable solid base. All 
the hairs are here again unbranched, but the marginal cells project at their 
upper ends as blunt bosses, giving the margin a deeply sinuous outline. 
Thus their structure appears to be an advance upon the simple type of hair 
seen in Matonia. The difference is due to the longitudinal divisions at the 
base, but still the type of hair is essentially the same. In Cheiropleuria the 
type of hair conforms more nearly to that of Matonia than to that of 
Dipteris . Each is long and unbranched, and is always composed of 
Text-fig. 5. A juvenile leaf of 
Platycerium Veitchii , for comparison 
with Text-Figs. 3 and 4. x 3. 
a simple filament of cells. But the induration is much less pronounced 
than that in either Matonia or Dipteris . Each may consist of as many 
as twenty or thirty cells. The type of hair seen in Cheiropleuria is thus 
probably as primitive as in any of these Ferns. On the other hand, in 
Platycerium the leaves, while young, and especially the fertile regions, are 
very efficiently covered by the well-known ‘ indumentum ' of tufted hairs. 
Each hair consists of a stalk, with a multicellular distal star of about six 
rays. Clearly this is a more advanced state than that of any of the Ferns 
mentioned above. 
A more complex type of dermal appendage is seen on the rhizome of 
Platycerium. In P. alcicorne the apical bud is densely covered with scales, 
