TREE FERNS OF NORTH AMERICA—MAXON. 489 
and size of leaves, fern students up to a comparatively recent time have 
been dependent mainly upon the chance and often inexact observa- 
tions of collectors, who as a rule have not been well acquainted with 
the group, and upon the characters offered by conservatory specimens 
As has been pointed out, excellent distinguishing characters ie 
afforded by the trunk and by the vascular parts of the frond, especially 
by the stipe bases, which are mostly armed with spines of different 
kinds for different species and clothed with equally characteristic 
scales. Yet these are the very parts usually omitted from collections 
which are likely to consist only of a small section of the blade, often : 
single pinna. To know from such scant material the real characters 
of plants with stems 10 to 50 feet high and leaves 5 to 15 feet long is 
obviously impossible; and many have been the complaints of fern 
writers from Sir William Hooker’s time almost to the present upon the 
inadequateness of herbarium specimens. Within the past two or 
three decades, however, and with the development of more convenient 
and ready means of travel, the practice of sending investigators to col- 
lect material of their own special groups has become general. Very 
full and valuable data are being obtained in this way, in marked con- 
trast to the incomplete and piecemeal information conveyed under the 
old method; and it has been found feasible to collect and dry charac- 
teristic sections of the trunk of most species, in addition to the stipes 
and the lower, middle and upper pinnae of the fronds. It is upon the 
basis of carefully selected and complete herbarium material of this 
sort, supplemented by photographs and by exact field data as to size, 
form, structure, and color of the various parts, that an adequate knowl- 
edge of tree ferns will finally be built up. 
EXPLANATION OF PLATES. 
PLATE 1. 
Group of tree ferns (Cyathea princeps), near Sepacuité, Alta Verapaz, Guatemala. 
Photographed by Mr. G. N. Collins, April 16, 1904. 
PLATE 2. 
View from the Adjuntas Road, Porto Rico, showing plants of Cyathea arborea.’ Photo- 
graphed by Mr. G, N. Collins, July 11, 1901. 
PLATE 3. 
Two forms of trunk of Cyathea arborea (see p. 472), collected in the valley of the Rio 
Bayamita, southern slopes of the Sierra Maestra, eastern Cuba, altitude 
2,000 to 3,500 feet, April, 1907; fig. a, Maxon 3909; fig. b, Maxon 3906. Both 
one-half natural size. 
Puate 4. 
Coffee warehouse at Sepacuité, Guatemala; excepting the five heavy supporting tim- 
bers the upright sides are entirely of tree fern trunks. Photographed by 
Mr. G. N. Collins. 
