Trithuria sect. Hydatella

Trithuria sect. Hydatella is a section within the genus Trithuria^[2] native to New Zealand and Australia.^[3]

Trithuria sect. Hydatella Temporal range: 16.07 –0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Early Miocene – Recent[1]
Flowering Trithuria inconspicua
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Order:	Nymphaeales
Family:	Hydatellaceae
Genus:	Trithuria
Section:	Trithuria sect. Hydatella (Diels) D.D. Sokoloff, Iles, Rudall & S.W. Graham[2]
Type species
Trithuria australis (Diels) D.D. Sokoloff, Remizowa, T.D. Macfarl. & Rudall[2]
Species
See here

Description

Trithuria inconspicua

Botanical illustration of Trithuria australis

The apocarpous berry fruit is indehiscent.^[4] Pericarp papillae and pericarp ribs are absent.^[2] The fruit stalk bears a distal constriction, serving as an abscission zone.^[5] The seed cuticle is thick.^[2]

Taxonomy

It was first described as Hydatella Diels by Friedrich Ludwig Emil Diels in 1904.^[6][7] After the former genus Hydatella Diels was merged into Trithuria Hook.f. in 2008,^[8] the section Trithuria sect. Hydatella (Diels) D.D. Sokoloff, Iles, Rudall & S.W. Graham was described by Dmitry Dmitrievich Sokoloff, William J. D. Iles, Paula J. Rudall, and Sean W. Graham in 2012.^[2]

Species

It has four species:

• Trithuria austinensis D.D.Sokoloff, Remizowa, T.D.Macfarl. & Rudall^[2]
• Trithuria australis (Diels) D.D.Sokoloff, Remizowa, T.D.Macfarl. & Rudall^[2]
• Trithuria filamentosa Rodway^[2]
• Trithuria inconspicua Cheeseman^[2]
  Trithuria inconspicua subsp. brevistyla K.A.Ford

Etymology

The section name Hydatella comes from the former genus Hydatella Diels,^[2] whose name is derived from the diminutive of ύδωρ (hydor) meaning water.^[9]

Distribution

Its species occur in New Zealand (North Island, South Island) and Australia (Tasmania, Australian mainland).^[3]

Phylogeny

Trithuria sect. Hydatella split from Trithuria sect. Trithuria about 16 million years ago in the Early Miocene.^[1][10]