Phylogenetic Relationships of the Subfamily Taenitidoideae, Pteridaceae

2004·9.1 MB·English

by  Patricia Sánchez-Baracaldo

American
Fern Journal 94(3):126-142
[2004J
Phylogenetic
Relationships of the Subfamily
Taenitidoideae, Pteridaceae
Patricia Sanchez-Baracaldo^
Department
of Integrative Biology and University Herbarium,
University of California,
CA USA
Berkeley, 94720,
Abstract.—
Thirteen genera
are traditionally recognized in the subfamily
Taenitidoideae,
A
Pteridaceae. phylogenetic study of this subfamily, based on both morphological and molecular
was
performed
data, using an exemplar
approach.
Representatives of the followincr genera were
included
in the analyses: Janiesonia, Eriosorus, Pterozonium, Syngramiua,
Taenitis, Austro-
gramme, Pityrogromma, Anogramma,
Actiniopteris, Onychium, and
Specimens and
Afropteris.
DNA
samples were
not available for Cerosora and Nephopteris, so they were excluded. Three
species were chosen
outgroups:
as Pteris multifida, P. quadriaurita, and Coniogramme
froxineo,
all
which A
of are restricted to the Old World. robust phylogeny was generated based on 26
morphological
characters, 578 base
pairs of the plastid gene rps4 and from
partial data the
intergenic spacer The
rps4-trnS. results reject the hypothesis of monophyly of the subfamily
as
presented by Tryon
However,
et al. (1990). the results support the monophyly of a well-supported
clade
confflsting of Jamesonia, Eriosorus, Pterozonium, Austrogramme, Syngramma,
Taenitis,
Pityrogrammo, and Anogramnia. The New World
genera Jamesonia and Eriosorus form mono-
a
phyletic group, and Pterozonlum more
is closely related to the Old World genera, Austrogramme,
Syngrammo,
and
Toenitis.
Although,
ferns are the second most
species-rich group of land plants, they
have been
relatively understudied compared
the
to largest group, the flowering
plants. Several comprehensive
on
studies pteridophytes have
looked
at
morphological
and/or molecular
characters from
a phylogenetic perspective
Wolf
Wh
(Wolf
number
increasing
of studies have looked
closely
at lower-level relationships
(Conant
et al., 1995; Haufler et 1995; Gastony and
al., Rollo, 1995; Pryer, 1999;
Gastony and
Johnson, Smith and
2001;
Cranfill, 2002; Ranker
et al, 2003).
Such
phylogenetic
studies lower taxonomic
at levels are sorely needed
to
understanding
facilitate
of evolutionary
processes
of and
diversification
biogeographic among
patterns
pteridophytes.
The
Pteridaceae
and
is a large diverse family homosporous
of with
ferns
worldwide
a nearly
distribution (Tryon The
et al, 1990]. family comprises
34
genera New
that are mostly A
restricted World
to the (Tryon
et al, 1990).
number
considerable
of species found
are exposed and
in rocky
environments,
although some members
of the family found
are
in a diverse array of mesic
habitats (Tryon
et al, 1990). Phylogenetic
relationships within
the Pteridaceae
Current Address: School
^ of Biological
Sciences, University of Woodland
Bristol, Road,
Bristol,
BS8
lUG, UK.
SANCHEZ-BARACALDO: RELATIONSHIPS OF SUBFAMILY TAENITIDOIDEAE
127
Of
are poorly understood. the six subfamilies recognized in the family (Tryon
et qL, 1990], only the Cheilanthoideae has been extensively studied from
and
a phylogenetic perspective, using plastid rhcL nuclear ITS nucleotide
sequences (Gastony and RoUo, 1995, 1998]. Some members of subfamily
Taenitidoideae were included in a larger phylogenetic analysis based on rhcL
nucleotide sequences (Gastony and Johnson, 2001; Nakazato and Gastony
2003), and more studies are needed to understand the phylogenetic relation-
among
ships amongst members. Phylogenetic relationships within and the
its
other five subfamilies are yet to be resolved.
Some
Subfamily Taenitidoideae circumscribe morphologically.
difficult to
is
most and
of the distinctive diagnostic morphological characters are not
members
borne
consistent across of the group. In general, the sporangia are
all
along the veins in exindusiate soral lines, or on an inframarginal commissural
vein, but in some genera the sporangia are borne the leaf margin and are
at
protected by a false indusium. Most genera in the Taenitidoideae have
paraphyses associated with the sporangia, but some genera completely lack
paraphyses.
According to the most recent taxonomic review (Tryon et aL, 1990) thirteen
which worldwide
genera belong to subfamily Taenitidoideae, has a distribu-
tion. Jamesonia, Eriosorus, Pterozonium, and Nephopteris are primarily
neotropical (Tryon aL, 1990). Pityrogromnia and Anogranima are mostly
et
restricted to the Neotropics, but the former extends to Madagascar, and the
subcosmopolitan. Actiniopteris primarily African, and SyngramiuQy
latter is is
and Austrogromme
Taenitis, are centered in southeastern Asia. Afropteris
is
Onychium
West and found
distributed in tropical Africa the Seychelles.
is
New
northeastern Africa, from Iran eastward to China, as well as in
fi:*om
Guinea. Cerosora a native of Borneo, Sumatra, and the Himalayas. The
is
members
traditionally recognized of subfamily Taenitidoideae exhibit a di-
ranging from moist and sheltered dry and open, and from
versity of habitats, to
Some
terrestrial to rupestral. species live in forests, in the understory growing
along streams, and a few species are rheophytes.
Old World genera Syngramma, and Austrogramme
Historically the Taenitis,
make up on number
have been considered a natural group based a of shared
to
morphological characters such as disposition of sporangia and paraphyses
Hennipman,
(Copeland, 1947; Holttum, 1959, 1960, 1968, 1975; Walker, 1968;
New
The World and Pterozonium have
genera Jamesonia. Eriosorus,
1975).
also been considered closely related to each other based on venation, blade
indument, and spores (A, Tryon, 1962). A. Tryon (1970) postulated that
among
advanced group mainly American
Eriosorus represents the least the
genera, and that its relationship to Pterozonium is not as close and is without
a clear lineal derivation. She also suggested that Jamesonia and Eriosorus are
and Jamesonia derived from more than one element
closely related, that in
is
Eriosorus. A. Tryon (1962) pointed out morphological similarities shared
New
between the Old and World genera of the Taenitidoideae, characters that
suggested a close phylogenetic relationship. Recent studies have suggested
that the Old World genera of the Taenitidoideae and Pterozonium originated in
128 ANfERICAN FERN JOURNAL: VOLUME NUMBER
94
3 (2004]
Gondwana
southern region before South America and Antarctica-Australia
Lower
separated during the Cretaceous [Schneider, Furthermore,
2001).
Pity-
rogramma and Anogramma
have been hypothesized to be closely related to each
other based on lamina and
architecture, sorus type, spores Tryon,
(A. 1962).
The aim was
general of this study to elucidate phylogenetic relationships
within the subfamily Taenitidoideae based on both morphological and
As
molecular working monophyly
data. a hypothesis, of the Taenitidoideae
A
as presented by Tryon et al (1990) was assumed. second aim was
to test
New
various hypotheses and among
of relationships within Old and World
the
A
aim
subfamily.
third
h
Material and Methods
—
Specimens Examined. Using exemplar
the approach, 20 species were chosen
to
represent eleven
of the thirteen genera currently recognized
in the subfamily.
DNA
Vouchers and
samples were
not available Cerosora and monotypic
for the
A
genus
Nepbopteris, so they were excluded. complete
used
list of the taxa in
this study is presented in Table 1, which refers to vouchers that were used to
generate sequence
data for rps4 as well as morphological
characters.
Morphological
characters were
also corroborated with other specimens housed
the University Herbarium,
at University
of California, Berkeley Most
[UC). of
DNA
the vouchers included Two
in this study are housed UC. specimens
at are
at the Nationaal Herbarium Nederland, Leiden and
one specimen
(L),
is at
Institut fur Systematische Botanik
der Universitat Zurich
(Z).
A
multiple outgroup approach was
used
to resolve plesiomorphic
characters
within
the ingroup (Maddison
et 1984). Pteris and
al., multifida P.
quadriaurita from
the subfamily
Pteridoideae were included based on
broader-scale previous
phylogenetic
studies [Hasebe
et al, 1995; Fryer al,
et
Coniogramme
was
1995).
fraxinea also included more
as a distantly related
outgroup
(Hasebe
et al, 1995; Pryer et al, 1995; Gastony and
Rollo, 1995;
Gastony and
Johnson, Coniogramme was
2001).
initially placed in the
cheilanthoids by Tryon
et (1990) but subsequently shown
al. be
the
to sister
other
to traditional Pteridaceae
plus
Vittariaceae (Hasebe Gastony
al, 1995;
et
and
Rollo, 1998; Nakazato and Gastony
2003). All three outgroups
are
Old
restricted to the World.
Morphological
Character
Analysis.—The
following were
criteria considered
when
selecting morphological
characters
for this study: characters should
1)
exhibit greater degree of among OTUs
variability
than
within, thus providing
discrete character
states; characters should
2) lack due
variability
to
ecophenotypic
factors; characters should
3) be independent each
of other
and
(Wiley,
1981); there should be good
4) a basis for hypothesizing homology
across the study group.
As
a approach, on
first literature
traditional
classifications of genera in the
Taenitidoideae, and
previously
published
morphological
were
descriptions
SANCHEZ-BAR.\CALDO: RELATIONSHIPS OF SUBFAMILY TAENITIDOIDEAE
129
DNA
Table 1. Species used as a source for and rps4 sequence data for this study. Most material
was preserved in silica gel, two were herbarium specimens, and a few were fresh material.
Collector/Source/ Geographic Accession
Genus
Species Herbarium i i number
origui
Actiniopteris australis Sanchez-Baracaldo Unknown, native AF321693
Link 360
(L.f.) (UCJ of Africa
Afropteris barklyae Kramer 11086 (Z) Seychelles Islands AF544984
(Baker)
Anogramma
Unknown
chaerophylla Sanchez-Baracaldo AY357705
(Desv.) Link 361 (UC)
Anogramma
guafemalensls Smith 2586 (UC) Costa Rica AF321699
(Domin) Chr.
C.
New
Austrogramme decipiens van derWerff 16114 Caledonia AF321702
Hennipman
(UC)
(Mett.)
New
Austrogramme marginata D. Hodel 1454 (UC) Caledonia AY357704
Fourn.
(Mett.j E.
UC
Coniogramme
fraxinea Bot. Card 58.0375 Java AF321696
(D. Don] Fee ex Diels (UC)
Erlosorus flexuosus Copel. Sanchez-Baracaldo Colombia, AF321710
215 (UC) Cundinamarca
Eriosorus insignis (Kuhn) A. Salino 3010 (UC) Brazil, Minas Gerais AF321708
Tryon
A.
F.
Eriosorus rufescens (Fee) Sanchez-Baracaldo Colombia, Antioquia AF321719
Tryon
A. 268 (UC)
F.
Jamesonia alstonii Sanchez-Baracaldo Colombia, Cocuy AF321747
A, Tryon 246 (UC)
F.
Jamesonia imbricata Sanchez-Baracaldo Colombia, Guantiva AF321756
&
(Sw.) Hook. Grev. 252 (UC)
Onychium japonicum B. Ornduff 10278 (UC) China, Yunnan AF321697
Kunze
(Thunb.)
UC
Pityrogramma austroamericana Bot. Gard. 98.0063 Unknown, native of AF321698
Domin
(UC) Neotropics
UC
80059 Unknown, AF321695
Pteris multifida Poir. Bot. Card. native of
Old World
(UC)
UC
Unknowm. AF321694
Pteris quadriaurita Retz. Bot. Gard. 67.1645 pantropical
(UC)
Pterozouium cyclosorum Brewer 1006 (UC) Venezuela, Bolivar AF321703
et al.
Sm.
A.
C.
Pterozouium reniforme Brewer 1005 (UC) Venezuela, Amazonas AF321704
et al.
Fee
(Mart.)
Syngramma
quinota M. Kessler 2273 Borneo, West AF321701
(L)
(Hook.) Carr. Kalimantan
Taenitis interrupta H. Schneider 1031 Borneo, Sarawak AF321700
(L)
Hook,
Grev.
et
reviewed (Ching, 1934; Pichi SermoUi, 1962; A. Tryon, 1962; R. Tryon, 1962;
Lellinger, 1967; Holttum, 1968; Atkinson, 1970; Holttum, 1970, 1975, Tryon and
From
Lugardon, 1991], this those characters that met the above criteria were
list,
new
and some
selected modified. In addition, characters not previously
were examined and
considered included. In the present study, non-applicable
characters were coded as missing data, an approach previously discussed in
AMERICAN FERN VOLUME NUMBER
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Table 2. Morphological data matrix for the cladistic analysis of subfamily Taenitidoideae,
See Appendix and
Pteridaceae. 1 for characters characters states.
number
Character
1
2
12345678901234
7890123456
Taxa
5 6
10110111110011 1120017701
famesonia imbricata
2
10110111110011
1120017701
Jamesonia
alstonii 2
10010111110010
012001??01
Eriosorus
insignis
10010111110010
0120017701
Eriosorus rufescens O&l
10010111110000
1010017701
Eriosorus flexuosus O&l
10020011010120
1010117701
Pterozonium
renifornie
1
20011110120 1020117701
10
Pterozonium cyclosoruw
1
22001110110
1000017700
Austrogramme
decipiens
1 1 ? 1
11722001110120
1000017700
Austrogramine marginata
1
11722001110110
1000017701
Syngramma
quinata
1
10022001110110
1000017701
Taenitis Interrupta
1
10200101111700
100010301?
Anogramma
guatemalensis
1
10200101111700
100010301?
Anogromma
chaeropbylla
1
01011700
100010201?
10
Pityrogramma
austroamericana
2 1 1
00001700 100110201?
10 10
Onychiurn joponicum
?
1 1
00101730
100110101?
oil
10
Actiniopteris austrolis
1 1
00101700
100110001?
2?
Afropteris barklyae
2
1
01111710
11? 100000211?
10
Coniogramnie
fraxinea
3
1
00000700100700
100000001?
Pteris multifida ?
1
00000700100700
100000001?
quadnaurita
Pteris
1
Maddison
when
Non-applicable
[1993]. characters occur taxa lack the structure
in question, for instance, in the present morphological
data color of scales
set,
was
Anogramma,
scored only
Pityrogramma,
for Onychiurn,
Actiniopteris,
and Coniogramme
Afropteris, Pteris, because the other genera lack
scales.
Some
morphological were
characters sought from mounted
cleared leaves on
Two
slides (Arnott, 1959) from each exemplar. to three slides were mounted
A
per exemplar.
total of 26 characters were included The
in the analyses. data
matrix with
the characters and character shown and
states in Table
is
2,
a detailed description of the characters used presented Appendix
in
is
1.
A
Molecular Characters.—
of the taxa studied and
list their respective
DNA
vouchers
is presented in Table Total genomic was
1. extracted using
DNeasy
Mini
Plant
Kits {Qiagen, Chatsworth, CA],
following the manufac-
The
turer's protocol. amplicons of rps4 were amplified by polymerase chain
reaction (PCR), using the forward primer and
rps5 reverse primer trnS (Souza-
PCR
Chies
et aL, 1997]. reaction mixtures each contained
0.5 units of
AmpliTaq
Gold
polymerase
(PE Applied
Biosystems], 5 |iL of the supplied lOx
mM
mM
niM
Buffer II (2.5 MgCl2], 0.1 of each dNTP, 2.5 of each primer, -50
DNA
ng genomic and
of
total purified water volume.
to
PCR
GeneAmp
Elmer PCR
cycles (Perkin
System
9600
thermocycler] were
programmed
an
as follows: initial hot start of 95^C 10 min
for to activate the
AmpliTaq
Gold
polymerase, 40 cycles [94°C for 30 60°C 45 and 72^
for
s, for
s,
SANCHEZ-BARACALDO: RELATIONSHIPS OF SUBFAMILY TAENITIDOIDEAE
131
PCR
2 min), and a 7 min final extension step at 72°C. products were visualized
X
1%
with ethidium bromide on which were run
agarose gels in Tris-borate/
1
EDTA
electrophoresis buffer (pH Amplicons were purified with the
7.8].
PCR
QIAquick CA)
purification (Qiagen, Chatsworth, following the
kit
manufacturer's protocol, and then processed by cycle sequencing and
BigDye-terminator chemistry (PE Applied Biosystems) on an ABI model 377
automated fluorescent sequencer in the Molecular Phylogenetics Laboratory
at
the University of California, Berkeley.
Sequence were by and
edited visual inspection of electropherograms,
files
mutations or changes were verified using the program Sequence Navigator (PE
Applied Biosystems). Alignments were performed by eye in nexus The
a
file.
final aligned data matrix consisted of 993 characters; 578 from the rps4 coding
region, and 415 from the intergenic spacer rps4-trnS. For Eriosorus and
famesonia, 413 bp from the intergenic spacer rps4-tTnS were included; twelve
distinct shared insertion/deletion regions were recognized in the final
alignment and each region was coded as a single binary character for the
maximum
Syngramma
parsimony For Pterozonium, Austrogramme,
analyses.
and Taenitis, 252 bp were included from the intergenic spacer rps4-frnS; nine
distinct shared insertion/deletion regions were recognized in the final
alignment and each region was coded as a single binary character for the
maximum
parsimony The whole
analyses. intergenic spacer rps4-trnS region
was excluded due to ambiguity in the alignment for the following taxa:
Anogromma
Pityrogramma
chaerophyllo, A. guotemalensis, austroamericana,
Onycbium japonicum, and
Actiniopteris australis, Afropteris barklyae, the
three outgroups.
—
Phylogenetic Analysis. The morphological data was compiled using
set
maximum
MacClade (Maddison and Maddison, parsimony and
4.0 2000]. All
PAUP*
bootstrap analyses were run in 4.0blO (PPC; Swofford, 1999). Multistate
characters were unordered, and uninformative characters were excluded in
all
maximum
For each parsimony analyses were performed, and
analyses. analysis,
stepwise addition searches were conducted with the following specifications:
random
1000 additions, tree-bisection-reconnection (TBR) branch-swapping,
MULPARS.
and Equally most parsimonious were summarized using
trees a
strict
consensus Bootstrap values were calculated (Felsenstein, 1985; Sanderson,
tree.
1989; Hillis and Bull, 1993) to provide a measurement of support. Bootstrapping
random
of data sets used 1000 replicates, with 100 addition starting trees
all
TBR MULPARS.
implemented each branch swapping, and The
for replicate,
three analyses that were carried out in this study are as follows: morphological
1)
molecular and both morphological and molecular
data; data; data.
2) 3)
Results
The morphological data set included 26 characters; of these, 25 were
parsimony-informative and one was autapomorphic. The molecular
data
set
AMERICAN FERN VOLUME NUMBER
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included 993 309 were which 186 were
characters; of these, sites variable of
parsimony-informative and 123 were parsimony-uninformative.
—
A
Morphological Analysis. most parsimonious was
single
tree (Fig.
1)
^ =
found at 50 steps (CI 0.70; RI 0.86). Only bootstrap values higher than
50%
weakly monophyly
are reported. Results of this analysis supported the
of the Neotropical genera, Jamesonia, Eriosorus, and Pterozonium, plus the
Old World genera Austrogramme, Syngramma, and Within
Taenitis. this
clade, Pterozonium was basal to Eriosorus and Jamesonia. Eriosorus and
Jamesonia together formed a monophyletic group. Eriosorus appeared be
to
paraphyletic containing monophyletic Onychium
a Jamesonia. japonicum,
and
Actiniopteris australis formed a monophyletic group within weakly
a
supported
clade including and
also Afropteris barklyae, Pteris multifida,
P. quadriaurita.
—
Molecular aAnNdD CCoommbbiinneedd DDaattaa AAnnaallyysseess..— The parsimony
analysis of molec-
ular characters generated two most
a total of equally parsimonious found
trees
= =
at 481 steps (CI 0.76; RI the consensus shown The
0.83); strict in Fig.
is 2.
parsimony
analysis of morphological and molecular combined
characters
resulted in a total of four equally most parsimonious found 539
trees steps
at
=
^
(CI 0.75; RI the consensus shown Only
0.82); strict is in Fig. bootstrap
3.
50%
values higher than
are reported.
Results for the molecular data and the combined data described
sets are
together because the consensus
strict topologies of both analyses agreed
in
almost every
aspect (Figs. 2, except for an unresolved node of the clade
3),
containing
Afropteris barklyae, and
Pteris multifida, quadriaurita
P.
(Fig.
3).
Both analyses support monophyly
the of clades containing Austrogramme,
Syngramma,
and
Taenitis, Pterozonium, well
as as the Neotropical clade of
Jamesonia and
Eriosorus. Eriosorus appears be and
itself to paraphyletic
includes a monophyletic Jamesonia. In both Anogramma and
analyses,
Pityrogramma form monophyletic which
a group, monophyletic
is sister to the
group
that includes Jamesonia,
Eriosorus, Pterozonium, Austrogramme,
Syngramma, and
Taenitis, with high bootstrap
support.
Pteris multifida, P. quadriaurita, and Afropteris barklyae formed a highly
supported monophyletic group
both
in analyses
(Figs. In the molecular
2, 3).
Af
Afropteris barklyae,
Pteris multifid
P. quadriaurita unresolved Onychium
and
is (Fig. Actiniopteris form
3). a well-
Afropt
clade
(Figs.
2, 3).
Outgroups.—Even
were
if all analyses rooted with both and
species
of Pteris
Coniogramme
fraxinea, and
Pteris multifida P. quadriaurita were
consistently
nested with
Afropteris
(Figs. 1-3). In the morphological
analysis, P. multifida
and
quadriaurita form
P. a monophyletic group
that A.
is sister to barklyae,
although with low
very
bootstrap support The
(Fig. relationship of the
1).
Onychium
Afropteris-Pteris clade to japonicum and
Actiniopteris
australis
is
weakly
supported
Both
(Figs. 1-3). molecular and combined
data sets strongly
BARACALDO:
RELATIONSHIPS
133
Jameson
imbiicata
ia
3
95
3
Jameson
ahtonii
ia
3
81
3
Eriosofus
insignls
66
66
4
2
Eriosonts
fufescens
Erioso
fiLsJlexiiosus
2
4
Pterozonhim
renlfonne
69
1
4
Pterozonium cyclosorum
1
60
3
Austrogramme
decipiens
52
1
AiLStrogramme marginata
1
1
Syngramma
gtwide
5
Taenitis intetrupta
4
Anogramma
guatemaletms
51
1
Anogmmma
chaerophylla
1
L
Pityrogramma aiistroamencana
Onychium japonicum
3 1
r4
1
2
Actinlopteris austmlis
2
54
3
barklyae
Afropteris
3 Pteris muUifida
72
1
3
quadnaurita
Pteris
Coniograinme fraxinea
Ftg. Parsimony analysis of morphological data set. Single most parsimonious tree of 50 steps
1.
= =
(CI 0.70; RI 0.86). Numbers above branches indicate bootstrap percentage values based on 1000
Numbers
replicates of 100 random addition sequence replicates each. of character state changes per
branch are indicated below the lines. The tree was rooted using the outgroups Pteris multifida and
and more member, Coniogramme
P. quadriQurita from subfamily Pteridoideae, a distantly related
fraxinea, as explained in tlie text.
a
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Jam
eson ia im bricata
10
99
11
Jameson
ia alstonii
8
94
57 Eriosonis
insignis
4
12
100
ms
Erioso flexuosus
Ji^ ^^
26
3
Erioso nts nifescens
65
96
Pterozonium reniforme
37 77 8
9
Ptervzonium cyclosorum
8
me
Aiistrogram decipiens
98
4
99
37
9
me
Austrogram margin a
83 at
90
7
4
52
100
Syngramma
gfande
12
19
Taenitis interrupta
13
Anogramma
giiatemalemis
32
89
22 Anogramma
chaerophylla
17
11
Pityrogf'amma aiistroamericana
16
Onychiiim japonicum
12
99
13
am
Actiniopteris
trails
20
54
61 Afropteris barklyae
10
65
2
100
Pteris multijida
6
6
quad
Pteris riaurit
10
Coniogramme
fraxinea
Parsimony
Fig. 2. analysis of molecular data set. Strict consensus of two most equally
= =
parsimonious trees at 418 steps (CI 0.76; RI 0.83). Numbers above branches indicate bootstrap
percentage values based on 1000 random
replicates of 100 addition sequence
replicates each.
Numbers
of character state changes per branch are indicated below the lines. Trees were rooted
using the outgroups Pteris multifida and P. quaddaurita from subfamily Pteridoideae, and a more
member, Coniogramme
distantly related
fraxinea, as explained in the
text.
SANCHEZ-BARACALDO: RELATIONSHIPS OF SUBFAMILY TAENITIDOIDEAE
135
between and
support the relationship Afropteris barklyae, Pteris multifida, P.
quadriaurita
(Figs.
2, 3].
Discussion
—
Phylogenetic Relationships. Bootstrap values robustly support the topologies
generated by the analyses of the molecular data alone and the combined data
weak
but are in the analysis of the morphological data Clade support
sets, set.
combined
values for the data sets are slightly higher than for the molecular
The employed
data set alone. outgroup rooting rejects the hypothesis of
monophyly
of subfamily Taenitidoideae as defined by Tryon et al, (1990). In
member
this study, Pteris appears to be closely related to a of the ingroup
[e.g.
Afropteris] suggesting that would be more appropriately classified with the
it
proposed by Tryon and Tryon However,
pteridois as initially (1982). all
analyses agree on the monophyly of a highly supported clade including:
Jamesonia, Eriosorus, Pterozonium, Austrogramme, Syngramma, Taenitis,
Anogramma, and Pityrogramma The most
(Figs. 1-3). robust analyses, the
molecular and combined data recover a well supported monophyletic
sets,
group including: Jamesonia, Eriosorus, Pterozonium, Austrogramme, Syn-
gramma, Anogramma, and Pityrogramma
addition,
Taenitis, (Figs. In all
2, 3).
analyses performed in this study indicate that Jamesonia and Eriosorus form
monophyletic group
a 1-3).
(Figs.
Based on morphological Pterozonium
the analysis of characters alone,
is
and
sister to the clade consisting of Jamesonia Eriosorus (Fig. this clade is
1);
defined here by acropetal (outward) sporangial maturation (character
7,
Appendix shared by these three genera. In contrast, the most robust
1)
DNA
and combined
analyses based on sequences alone the data sets suggest
New
more Old
that the World genus Pterozonium closely related to three
is
number
World Austrogramme, Syngramma, and
genera, Taenitis (Figs. a
2, 3);
of morphological characters states are shared by this clade, e.g., spore
ornamentation, sporangial disposition, and paraphyses disposition (characters
Appendix
and
7 12 respectively,
4, 1).
—
The presented study
Previous Hypotheses of Relationships. topologies in this
prompt previously proposed phylogenetic hypotheses.
discussion of several
Syngramma
The Old World genus Austrogramme closely related to and
is
Syngramma
Taenitis, as postulated by Walker (1968). In all analyses, and
hypothesized by Copeland and Holttum
Taenitis are closely related, as (1947)
Syngramma and Austrogramme
(1960, 1975), with Taenitis being basal to
(Figs.
2, 3).
Although, A. Tryon (1962) postulated that the neotropical genera Pterozo-
nium, Eriosorus, and Jamesonia constitute a natural group, she later (1970)
stated about Eriosorus that, "the relationship to Pterozonium is not as close and
The study
is without clear linear derivation." results in this (Figs. 2, 3) suggest
more Old World
that Pterozonium actually closely related to the genera
is
Syngramma, and proposed by
Austrogramme, Taenitis (Figs. as Schneider
2, 3)