Biogeography of Malvaceae
New Zealand here is the New Zealand Botanical region, which includes the North Island, South Island, Stewart Island and their offshore islands, the Kermadec Islands, the Three Kings Islands, the Chatham Islands, the New Zealand subantarctic islands (Antipodes, Auckland, Bounty and Campbell Islands, and the Snares), and also Macquarie Island with the Australian subantarctic islands. There is an online copy of the Flora of New Zealand Series [1, 2], which gives the distribution of native and naturalised mallows within this region, which is supplemented by papers reporting subsequently naturalised plants [3, 4, 5, 6, 7, 8]. (Mallows are absent from the subantarctic islands [9, 10, 11].)
The climate of the New Zealand Botanical region varies from subtropical in the Kermadec and Three Kings Islands, and in the north of North Island, to cool temperate in the subantarctic islands. The exposed nature of the southerly islands makes them climatically challenging to mallows.
The Malviflora of the New Zealand Botanical Region is much sparser than that of Australia; instead 59 genera and 600 or more species there are three endemic (Entelea, Hoheria and Plagianthus) genera with about 10 species (the number of species of Hoheria is unclear), and two possibly native species of Hibiscus. When naturalised species are included the count of genera rises to 13.
Entelea belongs to tribe Sparrmannieae (Grewioideae), and has a northerly distribution between the Three Kings Islands and the northernmost parts of South Island. Hoheria and Plagianthus belong to the Plagianthus alliance within subtribe Abutlinae (Malveae, Malvoideae), which is otherwise mostly or completely (depending on definition) Australian. Of the 6 species of Hoheria 2 are endemic to South Island, 1 to North Island, 1 to the Poor Knights Islands (offshore of North Island), and the remaining two shared between North and South Islands. The two species of Plagianthus are both found in North, South and Stewart Island, and in the Chatham Islands.
Both species of Hibiscus (Hibisceae, Malvoideae) found in New Zealand are widespread in tropical and subtropical regions of the Old World. Two forms from the Hibiscus trionum complex are found; a local form found in the Auckland area, and a more widespread weedy form. The other species of Hibiscus present is Hibiscus diversifolius.
Most of the naturalised and casual species all belong to subfamily Malvoideae, but Sparrmannia africana (Grewioideae) is also naturalised. The most diverse genus is Malva, with 8 species recorded in New Zealand.
Counts of genera by island group
Species counts for genera (numbers in brackets represent naturalised and casual species)
state and territory counts
Species distributions (N represents naturalised species, C casual species)
Malvaceae in New Zealand Botanical Region
Chatham Islands, Kermadec Islands, North Island, South Island, Stewart Island, Three Kings Islands
Biogeography of Malvaceae
© 2007 Stewart R. Hinsley