Abstract
Of 75 regions, some continental and others insular, the diversity as expressed in the number of Phanerogam genera is compared. As could be expected it is found that richness in both continental and insular regions is positively correlated with size and with proximity to source areas. In comparable continental and insular regions the former are always richer; increase in the number of genera with increasing size is stronger in the former. There are various factors disturbing the relations between size/diversity and isolation/diversity. The role of these factors, such as climate, age, topography and the like are discussed. It is shown that isolated islands are not always poor (New Caledonia, Fiji, Lord Howe I., Rapa, etc.). On the other hand the poverty of islands (e.g. New Zealand) need not be primarily due to the distance from a source area but may be caused by impoverishment of an originally rich flora. Once isolated, an island flora is much more subject to losses than a continental area where the losses in general may be readily replenished. It would be wrong therefore to conclude on the basis of poverty that an island has always been as much isolated as it is at present. Not only are isolated islands in general poorer in genera, there are also less genera per family than in a comparable continental area. This is shown to be caused by a preponderance of families represented by a single genus in the former.
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Claims 10
Claim · model-written summary
richness in island and continental floras: positively correlated
Verbatim
e0“richness in both continental and insular regions is positively correlated with size”
t0“Phanerogam genera”
Claim · model-written summary
richness in island and continental floras: positively correlated
Verbatim
e0“richness in both continental and insular regions is positively correlated with size and with proximity to source areas”
t0“Phanerogam genera”
Claim · model-written summary
richer in island and continental floras: richer
Verbatim
e0“In comparable continental and insular regions the former are always richer”
t0“Phanerogam genera”
Claim · model-written summary
increase in the number of genera in island and continental floras: stronger
Not reportedSetting
Verbatim
e0“increase in the number of genera with increasing size is stronger in the former”
t0“Phanerogam genera”
Claim · model-written summary
not always poor in island and continental floras: not always poor
Verbatim
e0“isolated islands are not always poor”
t0“Phanerogam genera”
Claim · model-written summary
poverty of islands in island and continental floras: nr
Not reportedDirection
Verbatim
e0“the poverty of islands (e.g. New Zealand) need not be primarily due to the distance from a source area but may be caused by impoverishment of an originally rich flora”
t0“Phanerogam genera”
Claim · model-written summary
losses in island and continental floras: much more
Verbatim
e0“Once isolated, an island flora is much more subject to losses than a continental area”
t0“Phanerogam genera”
Claim · model-written summary
poorer in genera in island and continental floras: poorer
Verbatim
e0“isolated islands in general poorer in genera”
t0“Phanerogam genera”
Claim · model-written summary
genera per family in island and continental floras: less
Verbatim
e0“there are also less genera per family than in a comparable continental area”
t0“Phanerogam genera”
Claim · model-written summary
genera per family in island and continental floras: nr
- Taxon
- Phanerogamt0
- Outcome
- genera per familye1
- Setting
- preponderance of families represented by a single genuse0
Not reportedDirection
Verbatim
e0“This is shown to be caused by a preponderance of families represented by a single genus in the former”
t0“Phanerogam genera”
e1“there are also less genera per family than in a comparable continental area”