Panamanthus, a New Monotypic Genus of Neotropical Loranthaceae

5 Pages·1991·3.5 MB·

by  Job Kuijt

NEW
PANAMANTHUS,
A
Job Kuijt
MONOTYPIC GENUS
OF
NEOTROPICAL
LORANTHACEAE'
Abstract
The monotypic genus Panamanthus Kuijt (P. panamensis (Rizz.) Kuijt) proposed to accommodate the Panamanian
is
&
mistletoe previously known as Struthanthus panamensis Barlow Wiens; an expanded and
(Rizz.) description
Panamanthus
illustrations are provided. It is suggested that is related to Gaiadendron G. Don, another monotypic
genus found approximately same
in the ecological zone.
The known
mistletoe species presently as Stru- acters prohibit placement in any of the first three.
&
thanthas panamensis (Rizz.) Barlow Wiens was Dendropemon often has pedunculate monads, and
member
originally described as a of the genus the bracteoles are sometimes fused in a cupulate
Phrygilanthus (Rizzini, 1960). As made clear by fashion. The anthers of Rizzini's species are nearly
&
Barlow Wiens Dendropemon
(1973), Eichler's genus Phry- dorsifixed, but has unequivocally
^//r/n//?w5 cannot be maintained for systematic and basifixed anthers. Also, the filaments of Dendro-
The pemon
nomenclatural reasons. only species of Phry- are laterally excavated, a feature shared
gilanthus that Rizzini mentioned as a possible with the continental Phthirusa but not with other
rel-
new The
ative to his species has subsequently been genera. stem roots of Rizzini's species have
vemoyed to Psittacanthus {Psittacanthus palmeri no equivalent in Dendropemon, and would be
it
&
&
Watson) Barlow Wiens; Barlow Wiens, extraordinary have Ca-
(S. to a low-elevation, strictly
1973). Rizzini's species was transferred to Stru- ribbean genus represented by a single species at
&
thanthas by Barlow Wiens (1973), although high elevations in Chiriqui. No one has suggested
these authors did recognize its unusual nature. affinities to Dendropemon, however, which clear-
is
There are two major morphological features in ly very closely related to Phthirusa and probably
which Rizzini's species differs from other known to Oryctanthus as well; the species would clearly
all
much
species of Struthanthus, First, has bisexual flow- be out of place there at least as as has
it it
ers, whereas the other species are strictly dioecious. been in Struthanthus, The disposition of S. pan-
Second, the inflorescence consistently monadic, amensis has been a continual problem since
is its
and
while that of the other species basically or entirely description, here propose that the species be
is I
triadic. Also, the prophyllar bracteoles associated treated as a monotypic genus with possible, but
with each flower are fused above the flower so as rather distant affinities to another monotypic genus
known same
to hide the entire ovary, a feature not in found in the ecological zone, Gaiaden-
i.e.,
d
any other neotropical continental Loranthaceae. ron
New
The
two features are elsewhere the
in
first
World known Oryctanthus Oryc- Panamanthus
only in Eichl., Panaman-
Kuijt, gen. nov. TYPE:
Van Maracanthus
tina Tiegh., Kuijt, and the Ca- thus panamensis comb.
(Rizz.) Kuijt, nov.
Dendropemon
ribbean Blume, and would
strict logic
Phrygilanthus panamensis
Ann.
Rizz., Missouri Bot. Gard.
placement one
necessitate of Rizzini's species in of
270-272.
47: 1960.
Of
those genera. these, only the last genus needs &
Struthanthus panamensis
Barlow Wiens,
(Rizz.) Brit-
to be considered, as various other structural char- tonia 25: 39. 1973.
acknowledge continuing financial support from the Natural Sciences and Engineering Research Council of
I
'
Canada. Karel U. Kramer of Zurich kindly provided the Latin diagnosis. Several collectors have made special efforts
in Chiriquj to collect this elusive species, and several curators have extended special courtesies; these efforts have
added
significant substance to this presentation.
~ Missouri Botanical Garden; Mailing address: Department of Biology, University of Victoria, Victoria, British
V8W
Columbia, Canada 2Y2.
Ann. Missouri Bot. Gard, 78: 172-176. 1991.
Volume Number
78, 173
Kuijt
1
1991 Panamanthus
mm
— — —
Panamanthus
Figure panamensis. Monad
1. a. Habit of plant in fruit. b. Inflorescence in bud. c. in bud
&
van der Werff Herrera 6330, LEA; McPherson 9380, LEA).
(a, b, c.
Inflorescentia indeterminata. monadica. bracteis nu-
with occasional formed from
epicortical roots
merosis caducis suffulta; flores hermaphroditi bracteolae
cm
branches; internodes to 6 long, somewhat^quad-
coalitae, cupulam iormantes et ovarium occultantes. ^,
.
when becommg
rangular young, soon Leaves
terete.
m
Scandent x cm
plants to 3 diam., with rather to 14 7 cm, decussate; petiole 1.5 long,
m
straight, pendant branches or more in length, blade thin, with evident pinnate venation, base
1
Annals the
174 of
Garden
Missouri Botanical
mm
'.(
»
k^.
J.!
**•
i V
b
I
i'
•«
' '
>
'J*;
^*
:-. i.
^
- t
/*
A*-
• «
E
E
'd
ft-
C
* 4
t *
f
d
cm
—
—
Figure 2. Panamanthus panamensis. a. Open flower, the two fused bracteoles visible below. b. Longitudinal
— —
—
Young
mature stamen shown Base Mature
section of bud, with separately, dorsal view. c. of flower. d. fruit. e.
—
inflorescence bud covered by scale leaves. Base of infructescence with old persistent scale leaves (a-c,
still f.
&
mibur DUKE; DUKE).
McPherson 9380, LEA; 13109, Luteyn 3786,
Teeri
d, e,
f,
Volume Number
78, 175
1 Kuijt
1991 Panamanthus
truncate or very obtuse, apex contracted con-
into slope of Volcan Baru, starting along impassable road
for-
cm
Boque
spicuous, slender to .5 long. Inflorescences
tail
1
1.750-1.900 m, McPherson 11343 (LEA, MO);
2-4 cm
vicinity
somewhat
quadrangular,
at anthesis, race-
of Cerro Punta, above Guadalupe, forested slopes above
mose,
indeterminate, in small axillary clusters, in-
STRI 2,300-2,450 m, McPherson 9380
cabin, (LEA,
subtended by caducous
dividually several pairs of
MO).
scale leaves and set in a craterlike corky rim,
Discussion
inflorescence peduncle very (2-3 mm),
short
fol-
6-8
monad
lowed by pairs of monads; peduncle The
several structural peculiarities of Pana-
mm
2-2.5
long, fused along its length with a bract manthus panamensLS when
outlined above, taken
mm
extending 4 beyond and
sharply acute; brac-
aggregate, sharply from
in distinguish other
it all
mm
%
teoles ca. 2 long, fused along the lower of
neotropical Loranthaceae. In terms of the
inflo-
where
their length investing the nearly hidden ova-
rescence and
associated features, the Australian
mm
the acute both
ry, free, tips 1 long; bracteoles genus Atkinsonia would seem to be the most sim-
and bracts with conspicuous whitish margins when However, such an
could only be
ilar. affinity re-
6-9 cm
dry; infrutescence elongating ma-
to at mote, as would be qualified by the
it strictly ter-
Flowers hexamerous,
turity. pale yellow, with pleas-
restrial habit of that genus, and the various primitive
ant odor, the petals very slightly dimorphic; mature
features associated with in the seedling stages at
it
mm
8-9 mm)
bud above
long, thickest (2 just the least some of which we can safely extrapolate from
middle, with prominently acute ovary very
tip; those of the closely related Gaiadendron
(Kuijt,
mm),
short calyculus inconspicuous, with Any
slightly 1963,
(1 1965).
affinity of this sort, therefore,
undulating rim; anthers dimorphic, basifixed or can only be tenuous.
nearly so, lower ones reaching to top of stigma, known
Unfortunately, nothing about the chro-
is
upper ones almost entirely beyond; pollen sacs four, mosomes Panamanthus
of panamensis, and
it is
long and slender, connective extending beyond as
precisely here that significant information might
mm),
a small spur; filament extremely short (0.5 be expected. The primitive of Atkinsonia,
trio
downward
continuing as a long buttress on petal Gaiadendron, and Nuytsia number
shares a basic
Pollen isopolar, diplosyndemicolpate, glabrate. Style of n 12, the chromosomes being very small
for
mm
&
straight, ca. 5 long, terete below but com- Loranthaceae (Barlow Wiens,
1971); con-
in
pressed by the anthers above; stigma undifferen-
trast, the small-flowered neotropical genera of Lo-
sometimes Nectary prom-
tiated, slightly oblique. ranthaceae Struthanthus have
like n the
8,
somewhat
inent, with undulating surface. Fruit chromosomes being among known
the largest in
cm
baccate, nearly diam., spherical, yellowish
1 the angiosperms (Wiens, 1964).
orange, its calyculus inconspicuous, viscin tissue The caducous
inflorescence bracts referred
to
mm
Embryo
insignificant. small (2 long), slender, in the above diagnosis have not, as far as am
I
lacking a swollen radicular apex maturity.
at aware, been mentioned in the literature, and con-
Apparently a Chiriqui endemic, but be looked
to trast strongly to other species of Struthanthus
all
for also in nearby Costa Rica, especially in the except two or three species that are clearly not
San
region east of Vito. related Panamanthus panamensis, such
to as S.
leptostachyus (Kuntze) G. Don.
Similarly incon-
Materials examined. Panama. CHlRlQUf: Boquete
spicuous and caducous bracts are normal Gaia-
in
Bajo Chorro, 6,000 Davidson 431
District, rainforest,
ft.,
may
(holotype, US; isotypes, F, GH), 392 (F not seen); cloud dendron, where they occasionally become
forest, northeastern ridge leading to Cerro Horqueta, elongated, and and
foliar, persistent (pers. obs.),
1,800-1,900 m, Luteyn 3786 (DUKE, Cerro Colora-
F);
also in Atkinsonia, where they are always per-
km N
do, cloud forest 50 of San Felix on the continental
& sistent (Barlow, 1966; Kuijt, 1981).
divide, 1,200-1,500 m, Mori Dressier 7825 (MO);
The Panamanthus
pollen of
on trail to Cerro Horqueta, in cloud forest, 6,000-6,500 is similar especially
ft.. Proctor 31935 (LL); mossy forest E of Guadalupe to that of Struthanthus oerstedii Standi. (Feuer
NE
&
along Rio Chiriqui Viejo, about 2 mi. of Cerro Punta,
1985)
Kuijt, but lacks distinctive, specialized
&
ridge of Cerro Respinga, Wilbur Teeri 13 109 (DJJKE);
W There no
features. are significant similarities with
km
disturbed cloud forest about 8 of Cerro Punta,
in
Gaiadendron
& the primitive trio" of monotypic
6,100-6,400 Almeda
the vicinity of Las Nubes, '''
ft.,
Nakai 3536 (CAS, LEA); along old road from Boquete genera which, however, shows extreme palynolog-
N
to Cerro Punta on cloud forest trail up to the slope of ical contrasts amone component eenera, as be-
its
Volcan Baru, 1,750-1,900 m, 8°50'N, 82°30'W,
Al- &
tween Nuytsia and Atkinsonia (Feuer
Kuijt,
&
meda, de Nevers McPherson 6166 (CAS, LEA);
Distr.
Thus
1980). appears again that great palyno-
STRI it
Bugaba, Cerro Punta, from house edge moun-
to of
tain across the river, 8<'52'N, 82°33'W, 2,200 m, van logical divergence is compatible with close affinities
&
der Werff Herrera 6330 (LEA, MO); on path up N in some mistletoe groups.
176 Annals of the
Garden
Missouri Botanical
&
L
Altitudinal preferences are often consistent with- D. WiENS. 197 The cytogeography of the
Taxon 291-312.
loranthaceous mistletoes. 20:
Thus,
individual genera of neotropical mistletoes.
in
&
1973. The of the
classification
Gaiadendron punctatum tends be a subparamo
to
^ ul i-
^ . c rhrygu-ai nt,nlus (= ii\Si o*tant*ihera)\
generic segregates ol
.
America and major
species both Central in
in its 26-39.
Loranthaceae. 25:
^f Brittonia
^^le
&
Andean South America 1989). In
area, (Kuijt, Feuer, M. KuijT. 1980. Fine structure of
S.
J.
contrast, Struthanthus has strong preferences for mistletoe pollen. III. Large-flowered neotropical Lo-
Amer.
ranthaceae and their Australian relatives.
and nowhere occurring J.
low middle elevations, at
34-50.
67:
Bot.
Panamanthus panamen-
noted
the elevations for
&
1985. Fine structure of mistletoe
(1,200-2,450 VL
m).
Loranthaceae.
5J5 Small-flowered neotropical
pollen.
187-212.
In summary, the monotypic generic status here Ann. Missouri Bot. Gard. 72:
On
KuiJT, 1963. the ecology and parasitism of the
proposed more adequately recognizes the unusual J.
Gaiadendron punctatum
Costa Rican tree mistletoe,
nature of the species. In this respect might be
it 927-
(Ruiz Pav6n) G. Don. Canad. Bot. 41:
&.
J.
noted most accepted genera of small-flowered
that
938.
neotropical Loranthaceae are more weakly sepa- 1965, The anatomy of haustoria and related
.
Gaiadendron Canad.
Panamanthus from organs of (Loranthaceae).
from each other than J.
rated
is
687-694.
Bot. 43:
For example, Phthirusa and Den-
other genera.
1981. Inflorescence morphology of Loran
—
dropemon are separable only on the basis of triadic
1-
Blumea
thaceae an evolutionary synthesis. 27:
monadic
inflorescences, respectively.
vs. 73.
The morphological of Panamanthus 1989. Additional notes on the parasitism of
isolation
.
New
World Loranthaceae. Pflanzen 64:
Beitr. Biol.
would seem warrant status as a monotypic genus,
to
115-125.
however, no matter what to primitive
affinities
its
Woodson
RlzzlNl, C. T. 1960. Loranthaceae. In: R. E.
same
or other mistletoe genera are. At the time, & W. Panama. Ann.
R. Schery (editors), Flora of
Panamanthus Struthanthus may, 263-290.
related to Missouri Bot. Gard. 47:
if is it
and monadic WiENS, D. 964. Chromosome numbers in North Amer-
because of bisexual flowers inflo- 1
its
Phoradendron,
ican Loranthaceae (Arceuthobium,
more
regarded prim-
rescence, be as significantly
PsittacanthuSy Struthanthus). Amer. Bot. 51:
J.
than that genus.
itive
1-6.
LlTEKATURE CiTED
A
Barlow, B. A. 1966. revision of the Loranthaceae
New
of Australia and Zealand. Austral. Bot. 14:
J.
421-499.