| Strasburgeriaceae | |
|---|---|
 | |
| Ixerba brexioides | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Crossosomatales |
| Family: | Strasburgeriaceae Tiegh. inSoler. |
| Genera | |
| Synonyms | |
Ixerbaceae | |
Strasburgeriaceae is a small family offlowering plants in the orderCrossosomatales, only found inNew Zealand andNew Caledonia. It contains twogenera,Strasburgeria andIxerba. Both genera have simple, evergreen, alternated leaves, often in worl-like clusters, with gland-tipped serrations,hermaphroditic,pentamerous flowers with persistent sepals, clawed petals, flat and long filaments that extend beyond the petals and a persistent style with a punctiform stigma.[1]
Fossil pollen namedBluffopollis scabratus, found in deposits from thePaleocene to theMiocene, is almost identical to the pollen ofStrasburgeria, although only half its size. The fact that it was found in western and southern Australia and in New Zealand suggests that themost recent common ancestor ofStrasburgeria andIxerba had developed by the time of the break-up of East-Gondwana.[2]
Recent phylogenetic analysis resulted in the inclusion of the genusIxerba (previously assigned to the monotypic family Ixerbaceae) in the Strasburgeriaceae. The following tree represents the most recent insights in the relationship between the Strasburgeriaceae and other families.[3]
While bothIxerba brexioides andStrasburgeria robusta share a base chromosome number ofx = 25,I. brexioides isdiploid (2n = 2x = 50), whileS. robusta is icosaploid (2n = 20x = 500). The massivepolyploidy inS. robusta may have furthered the adaptations that let it survive on theultramafic substrates found in themontane forest of New Caledonia.[4]
