52 
HOOT. 
Perhaps the most interosting specialization of the roots of forns, 
hut one ^vhich I have seen mentioned nowhere else, is the massing 
of very nnmeroiis roots, all densely covered hy a felt of long, hrownish, 
persistent root-hairs which form a structure for the storage of water. 
Appropriately to their function, these masses of hairy roots are commonly 
found on ferns growing on naked rocks or tree-trunks, hut never on 
ferns with abundant soil, nor on trunks laden with moss. Persistent 
root-hairs as organs of attachment are very common among ferns and 
other plants, and it is doubtless through roots clinging by such moans 
that these Avater-stores have been evolved. Obvioush', too, the deepest 
roots in every mass of this kind still fasten the plant to its support, but 
that more than the deepest layer in a mass, which is sometimes more 
than 2 centimeters thick, can serve in this way is of course impossible. 
There is every gradation from these tliick pads down to those so thin 
they may serve for attachment alone, as is the apparent case with 
Pohjpoditim macro phyllum. San Eamon ferns with a sufficient mass of 
felty roots so that they must store water are Nephrodium Foxii (on 
rocks), Davallia pallida, Loxogramme conferta (few), L. iridifolia, As- 
plcnium tenerum, A. Belangeri, AntropJiyiim latifolkim, A. reti-ctdatum 
(very thick pad)., Niphoholns nummular iwf olius (few), Polypodium 
accedejis (few), 1\ llJfl (few), and P. nigrescens, beside all humus- 
collecting species. Fuzzy roots are found on Antropliyuni plantagineum, 
Polypodium ZippeJii^ P. angusiatiimj P. aJhido-sguamahim, P. cqudiforme 
and Dryostachyum pilosum, growing on submossy trunks or subnaked 
rocks, the hairiness of the roots of P. angustatum being evidently depen- 
dent on the nakedness of their substratum. In contrast with the 
L 
preceding, the following epiphytes on mossy trunks have fine, naked 
roots: Humata parvula, Davallia hrevlpes, Mtcrolepis ciliata, lAndsaya 
Ilavicei, L. pnlcliella, Prosaptia contigua, Polypodium celebicum and P. 
F 
pahnatum. 
Aspleniiim epiphyticuui has roots of two kinds; those of unlimited 
length, positively geotropic, forming a jacket around the stem, diarch, 
flanked by sclcrenchyma, unbranched, with hairs along the sheltered 
sidej aiid roots 2 to 3 centimeters long, slightly negatively geotrojjic, 
freely branched, closely appro^sed to the support, clinging by copious hail's, 
of similar structure to the preceding but with more sclerenchynia. These 
are the clinging roots. The former, under favorable conditions, will 
reach the ground and then branch. A. scandens likewise has roots of 
two kinds. In various scandent ferns stems are massed, and hold water 
as these two Asplenia do by means of the stems and mantles of roots, and 
in a few cases, an in Lindsnya Merrilli, persistent, decurrent leaf bases 
or stipes are useful in the same way. 
The bracing "roots" of Nepltrolrpis are very familiar objects. Those 
of several species of Diplazium are very stiff and somewhat spreading 
