Cecropiaceae: Coussapoa and Pourouma, with an ... - CNCFlora

Distribution and Ecology
ruginea, P. formicarum, P. herrerensis, P. myrmecophila,
P. napoensis, P. ovata, P. phaeotricha,
as well as P. bicolor subsp. tessmannii, P. mollis
subsp. triloba, and P. tomentosa subspp. apiculata,
persecta, and tomentosa. A concentration
of taxa is found in the north-western part of this
region.
(b) The Guiana (or Guayana) region, the Lower
Amazon Basin (Brazil: eastern Para and Amapa),
including an extension to eastern Brazil, with
the following taxa confined or distinctly connected
to this area: Pourouma bolivarensis, P.
saulensis, as well as P. bicolor subsp. digitata, P.
melinonii subsp. melinonii, P. mollis subsp. mol-
lis, P. tomentosa subsp. essequiboensis and subsp. Pourouma shows many morphological simimaroniensis,
and P. velutina.
larities to the African genus Myrianthus (with 7
(c) The Pacific Coastal region (Colombia and species), revised by de Ruiter (1976). The sim-
Ecuador) to Panama, with extensions to Gua- ilarities are found in the habit, the leaf shape and
temala and through northern Colombia to north- dimension and their infraspecific variation, and
western Venezuela, with Pourouma hirsutipetio- the (variable) length of the petiole. Furthermore,
lata, P. oraria, P. bicolor subsp. chocoana and the staminate inflorescences show similarities,
subsp. scobina, and P. melinonii subsp. glabrata. but the pistillate ones are different, as they are
The features of the East-Brazilian populations capitate in Myrianthus, where the pistillate flowof
P. guianensis, P. mollis, and P. velutina, re- ers are sessile and clustered in a single head. Both
semble those of the material of the same species genera are macrospermous in contrast to the othin
the Lower Amazon Basin and adjacent parts er genera of the Cecropiaceae. The two genera
of the Guianas.
also show strong ecological similarities and are
Pourouma bicolor, P. melinonii, P. mollis and found in similar types of habitat. These two gen-
P. tomentosa have one (or two) morphologically era may also be regarded not only as genetically
distinct entities (subspecies) distinctly connected related but also as the most primitive among the
with the Guiana (Lowland) region and the ad- Cecropiaceae.
jacent part of the Amazon Basin. In P. bicolor The leaves of some taxa, Pourouma cecropiand
P. melinonii one or two disjunct subspecies ifolia and P. aspera subsp. digitata, resemble those
occur in the third center of the genus and in P. of Cecropia because of the great number of inguianensis
a disjunct subspecies occurs in north- cisions, but the leaves are never peltate as they
ern Venezuela.
always are in Cecropia. Leaves of some other
In the wide-spread species the material in the taxa resemble leaves of some Coussapoa species
Upper Amazon Basin is morphologically more (see p. 5).
variable than in the other parts of their distribution
ranges. Pourouma cucura shares this trait.
Systematic
In
Arrangement
most parts of the distribution range of Pouof
the
rouma the taxa (even those at the
Species
subspecific
level) can be recognized, and well-collected ma- On the basis of overall similarities, several
terial of adult specimens can readily be identi- groups of species can be recognized. Not all
fied. In contrast, the situation in the Upper Am- species can be placed with certainty into one of
azon Basin, especially in its northwestern part, them, however, as the staminate inflorescences
is rather unclear with regard to the delimitation are not known (as in P. bolivarensis, P. saulensis,
of subspecies (even species in some cases). In and P. stipulacea).
several species (e.g., P. bicolor, P. mollis, P. to- One group of species is characterized by havmentosa)
morphologically aberrant collections ing the tepals of the staminate flower almost enhave
been made, e.g., in the valley of the Rio tirely connate, forming an urceolate infundibu-
Santiago (Peru, Amazonas).
liform perianth with the filaments of the stamens
115
In some cases (P. cucura and P. tomentosa
subsp. persecta) the present data suggest the oc-
currence of a disjunction between populations in
the southwestern part and those in the north-
western part of the Amazon Basin.
The genus appears to be underrepresented in
a zone from southeastern to northwestern Para
largely consisting of'mata de cip6' and north of
the Rio Solim6es of patches of'campos de terra
firme' (Pires, 1973). A similar disjunctive gap is
found in Coussapoa (see p. 10).
Systematic Position of the Genus