86 
New Zealand Ferns 
IV. CYATHEA 
CYATHEA (cyathos, a cup). A genus of 120 
species, with 4 in New Zealand. Large tree-ferns, their 
classification based on a microscopic difference in the 
seed vessel — a cup surrounding the base of the seeds. 
C. DEALBATA 
( 30 ) C. dealbata (whitish). “Tonga,” ‘'Silver King.” 
There is no mistaking this noble tree-fern; the pure 
white underside of the fronds must attract the notice of 
the veriest tyro. 
Description . — Trunk 10 to 30 feet high, about 8 inches thick, 
stalks rather slender, clothed at the base with shining dark-brown 
scales, elsewhere covered with yellow-brown hairs that drop ofif 
as the frond becomes older. Fronds numerous, spreading hori- 
zontally, 6 to 12 feet long by 2 to 4 feet broad, green or yellow- 
green above, pure white below from a coating of deciduous 
powder. Seeds small, round, copious, contained in a cup-shaped 
vessel. 
Abundant throughout the Dominion, perhaps the most gen- 
erally distributed among the arborescent species. Sea-level to 
2.000 feet. 
