106 THE CHRISTMAS AND HOLLY FERNS. 
The Christmas Fern. 
To the hunter, the trapper and the rambler in the 
winter woods, the Christmas fern (Polpstichum acroste- 
choides) is a familiar species. In summer it is not espe- 
cially noticeable, but in the snowbound season, the 
cheerful, fresh-looking fronds are sure to attract the eye. 
lt isa most abundant species and suitable localities within 
its range where it cannot be found are exceedingly rare. 
All the Christmas fern’s fronds are produced early in 
spring. They rise in circular clumps from a stout root- 
stock and when uncoiling are thickly covered with silky- 
white scales that make them conspicuous objects in the 
vernal woods. As the fronds mature, the scales turn 
brown and many remain uponrachis and stipe, especially 
the latter, through the season. The fronds occasionally 
reach a height of three feet, and are thick, narrowly 
lanceolate, acute and once pinnate. The numerous 
narrow pinnules have finely serrate margins and are 
arranged alternately on the rachis. Each has a triangu- 
lar ear on the upper side at base. The fertile fronds are 
taller than the sterile and differ in having the upper 
third or half suddenly decreased in size, this part bear- 
ing the sporangia. The sori are arranged on the under 
surface in two or more rows lengthwise of the pinnules 
with two other short rows on the earlike projections. 
They are partly formed before the fronds unfurl and 
ripen early in the year, being among the first of our 
species in this respect. The sporangia early push out 
from beneath the peltate indusia and make the fruiting 
pinnules look like little assemblages of tiny brown ant- 
hills. One of these pinnules is shown in the Key to the 
Genera. 
