53 
, r 
ahoYo tlio ground. It has already boen mentioned that Achrostlchum 
aurenm somotinios has pnouniathodo-roots ^vliicli are not greatly differ- 
entiated. 
nuiius cor.i.Kc'ixxis. 
J 
The amount of study which has already been devoted to two of the 
most extraordinary specializations of ferns, thost! for colleetin^^ hun'ius 
and for association with ants, spare me the necessity of entering into tlie 
details of either. Of humus-collectors, we have at San h*amon the nost-. 
builders, Asplenium musaefolium, A. rinfllitidis and Dnjnarin rigidiila; 
Polypodium punctatum^ whicli maketj brackets of leaf-bases interlaid 
and overlaid with humus and detritus M'hich'are sometimes 15 centi- 
meters broad and almost as deep^ but whicli does not normally form 
round nests; P. Iteradeum and Drynarla quercifolia, which, in tlieir best 
development, form spiral brackets, tlie supporting leaves being in a single 
series, but imbricate; and Thayeria, wliicb makes a most perfect, inde- 
pendent receptacle with each leaf. Other l*]iilippine humus-collectors 
are Dryoslachijuni splendens in Mindanao and Luzon, and 'Tolypodiarri'* 
meyenianiun in Luzon. This character of D. spJcndcns is not generally 
recogniz(Hl and my determination might be in error, but it is based on 
a coj^parison with a plant of the type nujuber of Cuming's collection. 
Thayeria is so remarkable and recent a discovery that I take the 
liberty of repeating a part of the description, from this Jot'^nat. 
(Volume I Suppl. (1906) page 1G5). "Fronde solitaria in ramo laterale 
rhizoinatis endogenay eornucopiaeforme; ramo in fundo cornucopiae in 
radieulas multas dissipato." "In its liumus-collecting structures Thay- 
eria is wholh' unlike any other known plant, the specialization having 
gone beyond the frond to the rhizome. Each leaf is a unit, a complete 
receptucle, whollj' out of contact with the main rhizome. It is the 
most perfect of the humus-collecting organs developed in its group, 
the material collected being inclosed on all sides and protected against 
desiccation with a throughness not attained even by Asplenium yidus. 
The specialization of the branch end as a root bearer in the })ottom of 
the cornucopia is a very novel feature." 
MYRAIKrOPinLY. 
Our two rcumrktihlc myr/necophilous ferns, Polypodium sinnosiim and 
Lecanoptcris, have recently been thoroughly studied by Yajtp,-^ in whose 
paper the previous literature is summarized. With regard to the anat- 
omy, there is nothing essential to add; but with regard to the signif- 
icance of the bizarre form and :^hvchire of the^v and other myrmeco])h- 
ilous plants of this region, Yapp followed Treub and Goebel in a 
puzzling oversight of the service rendered the ]>lnnt by the ants, which 
insects furnish their hosts witli mineral food. 
^Ann. of- Hot. (1002) 16. 185. 
