\' 
65 
it can have originated eIsG\v]iere tlian in Lasirwa. The lertilo frond 
is too reduced to offer any clue, but the sterile is altogct]ier T.u,^trsea-like. 
As it is, so far as known, strictly endemic in tJio Philippines it is 
quite reasonable to look for its ancestry among the most similar riiil- 
ippine ferns. 
.With the same measure of probability, Strtioseniid may be regarded 
as an offshoot of Aspidium, not, in spite of tlic sparingly anaf^tomosing 
veinlets of Fleocnemia, but of Euaspidium, A. Griffithii is a species, 
in the 7nost similar Aspidhim group, witli "sori" anastomosing-- along 
the veins. Indusia, if present in the ancestral forms, would inevitably 
have been lost in the reduction of the fertile frond. Leptodiilm must 
also be derived from Aspidium, L. hnceolalus is still occasional! 
found with the sporangia confined to the Tunin veins (as in Loxo- 
gramme) ; and L. laiifolins usually has the "sori," at least until they 
are old, anastomosing along the veins instead of covering the frond, 
being in this respect like its possiljle relative IlctmcmUis. The insta- 
bility of the frond-form of many species of Leptochiivs is a familiar 
plxenomenon. 
If the Woodsiew of the Natarliclien Pflanzetifamdlien are a homo- 
geneous group, it has a common origin with the Aspidiece, the most 
primitive representatives of the two groups ])oiug much closer together 
in all respects than either is to the highly specialized members of its 
own tribe. In fact, they are so alike that it is impossible to call either 
the more primitive, and I have ascribed that place to Lasircea only on 
geographical grounds, and because it is now a great and conspicuous 
group. The primitive member of Woodsiece is Acrophorus. The genr 
eralized character of this fern is shown by its history. Hooker, who 
calls it Davallia (§ Leucostcgia), remarks: ^^ ^'Blume arranges it in Aspi- 
dixim, and expresses no doubt as to the propriety of So doing. Presl 
makes a distinct genus of it, and places it betw ecu Cydopicris and Lcu- 
costegia. Judging . froni his figure, T do not see how it differs from 
Davallia, but he says ^hocce genus Cystopteridi valde affine est, differt 
soris in venulis apicalibus,^ and under Leucostegta he says 'Acrophoro 
affinissimum est'" Diels ^^ says of it "Ilabituell an Diacalpe erinnemd; 
durch die gleich^oitige Entwickclung der Segmonte sowohl wie das Indu- 
sium von den Davallieen zu nnterscheiflon," the indiisinm being "breit 
eiformig, am Grunde angewachsen, sonst frei." 
, I.liave no doubt that all these authors were describing the >aui<' i^pecies, 
and that, so far as insufficient material is ever a justification, each was 
justified in his view as to the aflfinity of the plant. When I first found 
the plant, hitherto unknown in the Philippines. T ascribed it to Ladrcea 
as unhesitatingly as Elumc had done; but it is indeed strikingly like 
=>' SiH-cies Filiuuju 1 : 157. 
^-iS^at. Pilanzonfain. I, 4: 104. 
50146 5 
