The Southern Peninsula Flora and Fauna Association (SPIFFA) is based in Rosebud and covers the southern part of the Peninsula.
"We promote a scientific approach to biodiversity conservation and support the preservation of existing habitat and the systematic restoration of environmental values, habitat and biodiversity on both public and private lands through encouraging consultation and providing information, education and training. The famed SPIFFA links page has over 300 environmental, land management and other sites. The downloads page has a selection of natural systems and restoration related PDFs, ebooks and some handy software"

Also on the Peninsula is Birdlife Mornington Peninsula
"BirdLife Mornington Peninsula is the local branch of BirdLife Australia located on the Mornington Peninsula in Victoria."

PFNC has some joint activities with Ringwood Field Naturalists Club and Victorian Field Naturalists Club

Another group of interest is Environment Victoria.
"Independent and definitely not for profit, we’ve been working to look after Victoria’s environment since 1969."

APS (Australian Plants Society) Mornington Peninsula
APS Mornington Peninsula Inc is a group of plant lovers who enjoy meeting with like-minded people to share their enthusiasm and to increase their knowledge about growing Australian plants on the Mornington Peninsula, south of Melbourne.

Habitat Stepping Stones
Habitat Stepping Stones is a not-for-profit program to help people create wildlife-friendly stopovers in their own backyards.
Did you know that over half of Australia’s threatened species and ecosystems occur within the urban fringe? Victoria alone is home to 223 threatened animals. The Habitat Stepping Stones website shows people how they can make a real difference to their local environment, right in their own backyard. And they'll receive a colourful Habitat Stepping Stones plaque for their front fence (like the one shown below).

New SEANA website
SEANA (South East Australian Naturalists' Association) is an umbrella body for Field Naturalists Clubs, including ours.

Some sites of particular botanical interest are:

Royal Botanic Gardens Melbourne website

Australia's Virtual Herbarium
"Australia's herbaria house over seven million plant, algae and fungi specimens. Herbarium specimens are an important resource for research on the Australian flora and provide a permanent record of the occurrence of a species at a particular place and time. AVH provides access to the collecting data associated with these specimens."

Atlas of Living Australia
"The Atlas of Living Australia is a collaborative, national project that aggregates biodiversity data from multiple sources and makes it available and usable online. "

Plants at JSTOR (images of type specimens)
"Global Plants is the world’s largest database of digitized plant specimens and a locus for international scientific research and collaboration."