146
M.T.K. Arroyo et al.
the endemic Tasmanian genus Tasmannia (Ehrendorfer, SilberhauserGottsberger, & Gottsberg, 1979). Dawson (1972) suggests that monotypic
Tepualia in South America has affinity to Mearnsia, today found in New
Zealand , New Caledonia, New Guinea, and on the Philippines and
Solomon Islands. Myrteola seems to be closely related to Myrtastrum of
New Caledonia and Neomyrtus of New Zealand (Landrum, 1988). The
fossil record increases this already impressive list. Fossil pollen of South
American Embothrium has been found in Australia (M. Crisp, personal
communication). Excluding suspected cases of recent long-distance
dispersal (Hebe, Sophora section Edwardsia) , and Weinmannia, which
might have reached South America and New Zealand independently, the
above shows that there are about 21 woody angiosperm genera in the
cool temperate rainforest of southern South America , whose origins can
be traced to a southern Gondwanaland tie. Assuming that all seven
genera of South American rainforest gymnosperms evolved in southern
Gondwanaland , at least one third of woody genera of the rainforest are of
southern Gondwanaland origin.
To these Gondwanaland elements, not surprisingly considering the
interstitial continental position of the rainforest zone in the Tertiary and
Cretaceous, a substantial neotropical element can be added . Table 8.1
shows that there are 19 woody genera or sections of woody genera (about
25%) reported to occur in southern South America rainforest today
that are centered in South America with species growing in forest habitats
at subtropical and tropical latitudes. This substantial neotropical element
includes Antidaphne, Azara, Blepharocalyx , Chusquea, Crinodendron ,
Dasyphyllum, Desfontainia, Drimys, Escallonia, Fuchsia section Que/usia,
Hydrangea section Cornidia, Lepidoceras, Mutisia, Myrceugenia, Myrteola,
Rhaphithamnus , Schinus, Tristerix, and Ugni, among which are many
important rainforest trees and shrubs. The genus Dasyphyllum (Mutisiae)
has recently been considered on molecular grounds to be basal to the
entire Asteraceae family (Kim, Jansen, Wallace, Michaels, & Palmero,
1992). Undoubtedly endemic Luma, closely related to Myrceugenia
(Landrum, 1981) of the tribe Myrteae, also belongs here.
The overall distribution patterns of these neotropical genera are surprisingly concordant (Arroyo, Cavieres, Marticorena, & Munoz, 1995;
Landrum, 1981). Absence from the Amazon basin and surrounding areas
is commonplace. Typically there will be one or few species in the cool
temperate rainforest, a few in the adjacent mediterranean scrublands in
central Chile, and well-defined disjunctions on the eastern side of the
continent in the region of northeastern Argentina-southeastern Brazil
and/or in the northern tropical Andes. Some genera (e.g., Crinodendron,
Azara) show an intervening disjunction in north-central Argentinasouthern Bolivia. Disjunctions may be expressed at the infraspecific
level (e.g., Maytenus boaria, Lomatia hirsuta, Rhaphithamnus spinosus,
Myrteola myrsinites), at the infra- and interspecific levels (e.g., Myrceu-
M.T.K. Arroyo et al.
the endemic Tasmanian genus Tasmannia (Ehrendorfer, SilberhauserGottsberger, & Gottsberg, 1979). Dawson (1972) suggests that monotypic
Tepualia in South America has affinity to Mearnsia, today found in New
Zealand , New Caledonia, New Guinea, and on the Philippines and
Solomon Islands. Myrteola seems to be closely related to Myrtastrum of
New Caledonia and Neomyrtus of New Zealand (Landrum, 1988). The
fossil record increases this already impressive list. Fossil pollen of South
American Embothrium has been found in Australia (M. Crisp, personal
communication). Excluding suspected cases of recent long-distance
dispersal (Hebe, Sophora section Edwardsia) , and Weinmannia, which
might have reached South America and New Zealand independently, the
above shows that there are about 21 woody angiosperm genera in the
cool temperate rainforest of southern South America , whose origins can
be traced to a southern Gondwanaland tie. Assuming that all seven
genera of South American rainforest gymnosperms evolved in southern
Gondwanaland , at least one third of woody genera of the rainforest are of
southern Gondwanaland origin.
To these Gondwanaland elements, not surprisingly considering the
interstitial continental position of the rainforest zone in the Tertiary and
Cretaceous, a substantial neotropical element can be added . Table 8.1
shows that there are 19 woody genera or sections of woody genera (about
25%) reported to occur in southern South America rainforest today
that are centered in South America with species growing in forest habitats
at subtropical and tropical latitudes. This substantial neotropical element
includes Antidaphne, Azara, Blepharocalyx , Chusquea, Crinodendron ,
Dasyphyllum, Desfontainia, Drimys, Escallonia, Fuchsia section Que/usia,
Hydrangea section Cornidia, Lepidoceras, Mutisia, Myrceugenia, Myrteola,
Rhaphithamnus , Schinus, Tristerix, and Ugni, among which are many
important rainforest trees and shrubs. The genus Dasyphyllum (Mutisiae)
has recently been considered on molecular grounds to be basal to the
entire Asteraceae family (Kim, Jansen, Wallace, Michaels, & Palmero,
1992). Undoubtedly endemic Luma, closely related to Myrceugenia
(Landrum, 1981) of the tribe Myrteae, also belongs here.
The overall distribution patterns of these neotropical genera are surprisingly concordant (Arroyo, Cavieres, Marticorena, & Munoz, 1995;
Landrum, 1981). Absence from the Amazon basin and surrounding areas
is commonplace. Typically there will be one or few species in the cool
temperate rainforest, a few in the adjacent mediterranean scrublands in
central Chile, and well-defined disjunctions on the eastern side of the
continent in the region of northeastern Argentina-southeastern Brazil
and/or in the northern tropical Andes. Some genera (e.g., Crinodendron,
Azara) show an intervening disjunction in north-central Argentinasouthern Bolivia. Disjunctions may be expressed at the infraspecific
level (e.g., Maytenus boaria, Lomatia hirsuta, Rhaphithamnus spinosus,
Myrteola myrsinites), at the infra- and interspecific levels (e.g., Myrceu-