3. Soliva sessilis Ruiz et Pav.
This is the plant originally recorded by Cheeseman (1883: 285) as “Soliva pterosperma Less.?” with the distribution “Rangiriri and near Ngaruawahia, first seen in January, 1879.” Kirk (1899: 330) placed the plant under S. sessilis Ruiz et Pav., a course adopted subsequently by Cheeseman (1906: 1077, 1925: 1080) and Allan (1940: 152, 157).
Investigation of the genus by Cabrera (1949: 131) has shown that S. sessilis Ruiz et Pav. and S. pterosperma (Juss.) Less. are distinct entities, although confusion has existed in the application of the names for many years; he states that references in literature to S. sessilis subsequent to the publication of Grisebace's Symbolae (1879) have been, in fact, references to S. sessilis Griseb. (1879) which name is correctly a synonym of S. pterosperma (Juss.) Less. (1832), the name of a species differing markedly in achene characters from the true S. sessilis Ruiz et Pav. (1794).
In view of Cabrera's conclusions, it was anticipated that a change of name would be necessary for the material up to now placed under S. sessilis in New Zealand.
I have examined specimens collected from Rangiriri by Cheeseman, and which, although not dated, can, I think, be accepted as one of the original gatherings; also specimens from Ngaruawahia collected in May, 1885, by Kirk; and find that these and subsequent collections, with two exceptions, belong to the true S. sessilis Ruiz et Pav., and not to S. pterosperma (Juss.) Less. as would be supposed.
It is not clear from the descriptions of the New Zealand plants just which species has actually been referred to; neither Kirk (1899: 330) nor Allan (1940: 152) states whether the achenial wings are entire or lobed, although the plant figured by Allan (1940: 157; Fig. 57) clearly represents S. pterosperma (Juss.) Less., which species, according to herbarium material examined, was not recognised in New Zealand until recently.
The distribution as given for S. sessilis in New Zealand literature is largely correct, although it has been confused with S. valdiviana Phil. in several localities; in some localities the two species occur together, in other localities one or other of the species occurs alone.