Towards 3 million specimens: Hydroleaceae, Plocospermataceae, Tetrachondraceae & Carlemanniaceae

The following blog was written by Rebecca Camfield a digitiser in the Herbarium.

Since 2021 we have increased our digitisation capacity with the goal of getting to 1 million specimens imaged by Autumn 2024. Each digitiser is assigned a family of plants to work through. This series of blogs will spotlight the families that have been completed by a member of the team.

Hydroleaceae, Plocospermataceae, Tetrachondraceae and Carlemanniaceae are small families within the Lamiales.


Hydroleaceae consists of one genus, Hydrolea which is found globally in subtropical regions. This is shown in the distribution of our collections. It would be nice to boost representation from Central Africa, countries in West Tropical South America and from Queensland, Australia.

We hold 139 specimens of Hydroleaceae in our collections.

Top regions

No. of SpecimensHerbarium Filing Region
36India Bangladesh & Pakistan
24East Tropical South America
23North America
6Central America

Specimens of Hydroleaceae can be viewed here.


Plocospermataceae is a monotypic family of 1 genus and 1 species- Plocosperma buxifolium Benth. It is native to Central America and grows in seasonally dry tropical biomes. 

We hold two specimens in the collection, on is an isotype and the other a paratype, both specimens were collected over 100 years ago from Mexico and Guatemala.

Specimens of Plocospermataceae can be viewed here.

E00259360 6
Specimen of Plocosperma buxifolium collected in Guatemala, 1909 (E00259360)


Tetrachondraceae has two genera. Tetrachondra, found in New Zealand, Argentina and Chile. We have 1 specimen from New Zealand, a syntype of T. hamiltonii Pietre ex Oliv. collected in 1892!

Polypremum: found in Central America, the Southern states of the US, Colombia, Venezula and Suriname. Some common names are Juniperleaf or rustweed. We currently have no specimens of this genus.

It seems unusual to have not have more specimens of this family due to previous and current research into South and Central America.

Specimens of Tetrachondraceae can be viewed here.

E01038463 5
Specimen of Tetrachondra hamiltonii collected in New Zealand, 1982 (E01038463)


Carlemanniaceae is a small family with two genera, Carlemannia and Silvianthus with only specimens of Carlemannia represented in the collection. The distribution of Carlemannia is South China, Indo-China peninsular, Nepal, Bangladesh, Java and the North Eastern states of India.

We hold 43 specimens with the most collected in Bhutan and Nepal, which is unsurprising as these are regions where research has been focussed.

Specimens of Carlemanniaceae can be viewed here.

E00727576 6
Specimen of Carlemannia griffithii collected in Nepal, 1954

← Previous post

Next post →


  1. Scott Zona

    There’s a mistake in the first sentence of your section on Tetrachondraceae. You meant to say Tetrachondraceae, not Plocospermataceae.

    • Robyn Drinkwater

      Thanks for flagging this. The error has been corrected