Identification Fact Sheets of the Marine Benthic Flora of Southern Australia

the Flora of South Australia is off-line—a replacement is under development—some identification tools, a copy of the Census of South Australian plants, algae and fungi and other information is temporarily being made available on Know OurPlants until the new site is complete

These pictorial keys and fact sheets have been developed to aid in the identification of species from the rich algal diversity of our southern Australian coasts. Through the efforts of Emeritus Professor H.B.S. Womersley and those of his many students and helpers, some 90,000 algal specimens have been added to the State Herbarium of South Australia collection. There are also 20,000 prepared microscope slides of algal structures essential in species identification, accompanying these collections.

Honorary Research Associate of the State Herbarium of South Australia, R.N. (Bob) Baldock is the author of these fact sheets and has spent many years photographing the specimens and slides, and researching the content to provide this rich visual experience. These Algae Revealed fact sheets are designed to be accessible and based on expert-validated knowledge.

Table of Contents

Algae Revealed—an introduction

This is a collection of fact sheets of attached (benthic) marine algae from southern Australia, with summaries of their key features. Microscopic algae such as plant plankton are not included. It is intended to aid students and marine enthusiasts in becoming more familiar with the rich algal diversity of our southern Australian coasts. Many marine projects to be successful require algal identification. These fact sheets are useful aids to naming “that seaweed”.

What is included?

  • Each species has a page of coloured photos of whole plants and magnified views of important parts, generally taken from herbarium sheets (pressed specimens)
  • Another page has images of microscope preparations and descriptions of important structures written with a minimum of technical terms and provided in a standard format
  • There are also pictured keys to systematically identify some groups of algae, and pages that allow a quick visual comparison of different groups

How is it designed?

  • The arrangement of major groups —algal families— follows that of Womersley, H.B.S., 1984–2003 The Marine Benthic Flora of Southern Australia, Parts I, II, IIIA–IIID. Genera and species within a single genus are mostly placed in alphabetical order unless they are more easily identified by grouping them according to their shape.
  • Where possible, commonplace language has been used in order to reduce botanical terms

What are the fact sheets for?

  • Fact sheets highlight the important but often obscure characteristics of specimens that have to be found before you can confidently and correctly name species
  • Beware. They are not complete descriptions of the species. Obscure reproductive criteria may be omitted. Complete descriptions can be found in Womersley’s six volumes of the marine benthic flora that must act as the final and authoritative method of identification.
  • Fact sheets will give you a good start to identification, however.

How are the fact sheets arranged?

  • The number at the top right designates a particular phylum and family (and occasionally for large families, a tribe) and follows a similar scheme used throughout the Herbarium to organise specimens systematically
  • Icons indicate what special techniques may be needed, such as using hand lenses, sectioning and microscope work
fact sheet arrangement

Fact sheet symbols

  • The Features section looks at relatively superficial features that may aid in rapid identification of the species
  • Then follows the Special Requirements section, listing key features often demanding more detailed examination and skilled techniques
  • Coloured images of whole plants and close-ups are included. The Australian 10¢ piece alongside images is provided as a familiar scale (it is 24 mm across)
  • Microscope images showing key characteristics are found in Details of Anatomy

What are the numbers found alongside images?

  • Numbers starting with “A” refer to preserved specimens in the Herbarium collection, other numbers refer to prepared microscope slides

Why are images different in colour?

  • Blue images indicate the specimen has been stained with aniline blue to enhance the cell contents
  • Images with black backgrounds are made with dark-field microscopy, which highlights surface and edge features
  • Images with dull grey, greenish or pinkish backgrounds and bright margins are made with phase contrast or interference microscopy, which enhances colourless features such as cell walls, plastids and hairs

What is the correct way of using these fact sheets?

  • You must have the specimen you intend identifying—the voucher specimen—in front of you when making an identification. It can be pressed already, but preferably a fresh or preserved sample bearing reproductive parts should also be used. You may need to dissect or view this under microscopes to get a correct identification. The State Herbarium has some facilities for this. Seek help if this is necessary as some of the techniques required can be difficult.
  • To identify a major group or taxon, some simple pictured keys are provided. Then it is a matter of comparing the specimen you have with the critical features in the fact sheet.
  • Ultimately you will need to compare the features of your specimen with a full description in an authoritative marine benthic flora to be certain of a correct identification.

Marine Indicator Species of Southern Australian Reefs (top)

Pictured Keys of Common Southern Australian Marine Plants (top)

Major Groups

Brown Algae

Red Algae

Southern Australian Groups at a Glance (top)

Brown Algae

Red Algae

Green Algae

Phaeophyta—brown algae (top)

Phyllospora, floats and has strap-like blades

Phyllospora, floats and has strap-like blades

Rhodophyta—red algae (top)

Platoma australicum

Platoma australicum

Chlorophyta—green algae (top)

© 2024 Board of the Botanic Gardens and State Herbarium (Adelaide, South Australia)