TREE FERNS OF NORTH AMERICA——MAXON. 471 
the West Indian Cyathea elegans and Alsophila aquilina and the Costa 
Rican A. crassifolia), which exhibit this character to a marked degree 
in their young state, in age develop clean trunks, with definite even- 
surfaced scars.' The appearance of a trunk sheathed with broken or 
hanging fronds is much less attractive than that of stems from which 
the leaves are freely deciduous; yet a few, like Cyathea Brunei, more 
than make up in sheer massiveness whatever they may lack in ele- 
gance and graceful proportion. 
The arrangement of the leaves upon the stem may be observed 
best in species which have smoothish trunks, as in the common 
form of Cyathea arborea, shown in plate 3, figure A. In these the 
leaf scars may be either widely spaced or rather compactly set 
together, forming a rough but regular mosaic pattern; if the latter, 
the trunk is said to be tesselate. In most there may be noted a 
definite spiral arrangement, which differs according to the species 
and, exceptionally, among individuals of the species. In Cyathea 
aureonitens, however, and probably in others, the scars are not 
spirally arranged nor closely set, but uniformly appear in distinct 
horizontal zones, the six to eight leaf scars of each forming a separate 
distinct girdle about the trunk, 8 to 12 inches from the one above or 
below. 
RESTING PERIODS. 
Cyathea aureonitens has also another unusual feature, that of 
shedding all its fronds, after maturity, at one time, seasonally, 
a trait which it shares with several other species of the same genus, 
Cyathea concinna and C. Tussacii of Jamaica and C. insignis of 
Jamaica and Cuba. Concerning the first of these Jenman remarks 
that ‘‘like C. Tussacw, in the resting season, in late spring or toward 
midsummer, it drops all its fronds, the large stout trunk, a uniform 
diameter from top to bottom, standing, postlike, till growth begins 
again.”” With respect to C. Tussacit he writes, ‘‘In some instances, 
late in the resting season, about May or June, the fronds all drop 
away, leaving the bare trunk. When vegetation begins again a 
whorl is thrown up together.’”’ Cyathea insignis, also, ‘‘like the 
two preceding, makes its growth periodically, throwing out a tier of 
fronds at once and then resting for an interval.” In Cyathea 
aureonitens, as I have observed it in western Panama and Costa 
Rica, not only the large tripinnatifid fronds themselves but also 
their component leafy parts, the pinnez and pinnules, are sometimes 
freely deciduous; the latter were even observed to fall first, leaving 
the leaf stalks and nearly bare midribs of the huge leaves standing 
out temporarily like stout whip stalks before they also should fall. 
1 A similar tendency toward bushy growth from long-persistent leaves is noted in young plants of certain 
palms, as, for example, the common ‘‘coroho” of Jamaica (A cricomia fusifor mis). 
