16 AMERICAN FERN JOURNAL . 
of pubescence, and peculiarly developing indusium. 
From Polybotrya, it differs in having the sporangia 
confined to the backs of veins, in possessing an indusium 
and in being less dimorphic than true Polybotrya. 
The single species included is found in its typical state 
in Jamaica and Cuba. From Guatemala material has 
been collected which is recognized as a variety. 
E. 
“Tue Tree Ferns or Hawau.” Under this title, 
Vaughan MacCaughey has an interesting account! of 
the three species of tree ferns native in the Hawaiian 
Islands, with some discussion of tree ferns in general. 
The three kinds all belong to the genus, Cibotium, which 
also furnishes in the form of a Central American species, 
C. Schiedei, the most common tree fern in cultivation. 
The article gives special account of the economic 
value of the Hawaiian tree ferns. The trunks of the 
larger kinds are used to build corduroy roads through 
swampy places, a fact already noted by Maxon in his 
article on American tree ferns.2. Rude fences are some- 
times made by piling sections of trunks together. Flor- 
ists use them, as elsewhere, as the matrix upon which to 
grow various epiphytic plants such as orchids. Here 
in the United States where tree fern trunks are not 
available, the orchid grower makes use of the black 
root masses of the Osmundas. 
The rootstock and petiole scales of the Hawaiian tree 
ferns are very abundant, and under the name of pulu, 
have a considerable sale as mattress and pillow stuffing. 
At one time this sale was much greater than at present. 
Its sale in the United States was accelerated by special 
agents who would inquire on registering at a hotel 
1Am. Bot. 22: 1-9. June, 1916. 
? Smithson. Rep. 1911: 463-491. pl. 1-15. 
