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ORIGIN AND RELATIONSHIPS OF TAENITIS, 
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Taenitis and Schizoloma are unlike. Sckizoloma ensifolium, 
and other species of the genus, have the peculiar solid steles 
of the Lindsayae.^ But Definstaedtla seems to have in all species 
a solenostele with very short foliar gaps. As Gwynne-Vaughan 
states, Taenitis has a dictyostele very near in nature to a solen- 
ostele; it is so near in fact that in a rhizome with internodes 
16 mm long the foliar gaps may overlap by less than 1 mm. 
The only plant usually recognized as a very near relative 
of Dennstaedtia, in which I have found a dictyostele, is Sac- 
coloma mohiccanum, in which this structure is derived from a 
solenostele by the shortening of the internodes. Davallodes, 
which contemporary pteridologists have treated as a Microlepiaf 
has a complicated dictyostele; but my appreciation of its dis- 
tinctness from Microlepia has strengthened since I raised it 
to generic rank, and I now group it with the other epiphytic 
DavalUae, — Leucostegia, Davalliay Hiimata, Oleandra, etc., — in 
which open dictyosteles are the rule. 
Di^ymoglossimi has a real dictyostele, as have its polypodioid 
relatives, Goniophlebium, and the numerous related groups, and 
Hyvienolepis , Eschatogramme, and Paltoniiim Umceolatum. 
While technically bearing the same name, the stele of Taenitis 
is very much less like that of Drymoglossum than like any solen- 
ostele of the Dennstaedtia group. 
There are other characters of more or less interest which 
might be considered; but I believe that enough has been said 
so that nobody, having the plants in hand, will question the 
conclusion that Taenitis is a reasonably near derivative of 
Dennstaedtia, and not at all a near relative of Polypodium. We 
will now see that Taenitis is one of a very natural group of 
ferns, but a group as different as possible in composition from 
those which have borne its name. 
•Gwynne-Vaughan, Annals of Botany, 17 (1903) 689, Plate XXXIV, 
fig. 23, representing the stele of "Davallia" repens, might have been drawn 
from Schizoloma ensifolium. The data in this paper are of great taxo- 
nomic value, in spite of the statement that the "Anatomical characteristics 
do not, for the most part run parallel to ... . systematic position." The 
trouble is with the systematic position; thus, the author finds true solen- 
osteles in Dicksonia, Davallia, Lindsay a, Pteris and Polypodium; but the 
situation clears up when it develops that the DavalUae are all Microlepia 
or Leptolepia; the Dicksoniae, all Dennstaedtia; the Lindaaya, Odontosoria; 
the three species of Pteris, severally, Paesia, Histiopteris and Doryopteris; 
and the Polypodium, probably Hypolepis. When one recognizes genera 
which in a proper sense are genera, all of the apparently very diverse 
plants just named present themselves as near relatives. Contradicting 
the statement quoted above, Gwynne-Vaughan later suggests such a con- 
clusion. 
1973 
