Calflora is an independent organization dedicated to providing scientific information about California plants for research, conservation, and education. Calflora is supported by a mixture of funding from government agencies, grants from foundations, and private donors. Many other individuals and organizations also contribute data, expertise, and technical support.

Calflora was started in 1994 by Ann Dennis while at the US Forest Service to help assess how management practices might affect wildlife, plant diversity, and forest health. Originally an 8-character DOS filename, Calflora was a database of species information that could be downloaded and used on a personal computer. Subsequent versions made the taxon table a web-searchable database, and tested the three table concept of taxon, synonymy and occurrence data. An important early collaborator was the Texas A&M University Bioinformatics Working Group.

At the time (1990s), none of the sources of distribution information for wild California plants was complete enough to reveal biodiversity at local scales. Calflora was founded in part to become a single source of distribution data that integrated all other sources, and to be easily accessible to the public.

1997: CalPhotos
In 1997, Calflora began collaborating with the UC Berkeley Digital Library Research Project (DLP) to unite the Calflora database with a collection of wildflower images. The Calflora website was hosted on UC Berkeley servers. Digital Library Project staff members including Ginger Ogle, Joyce Gross, Jeff Anderson-Lee, and Loretta Willis provided invaluable assistance in advising and developing the original CGI-based technical infrastructure of Calflora. The nucleus of the CalPhotos wildflower image collection was formed by a donation of scanned slides from photographer and amature botanist Brother Alfred Brousseau of St. Mary's College. This was supplemented by additional major photo donations from the California Academy of Sciences, California Department of Food and Agriculture, and many private individuals. Since then, Calflora has worked with CalPhotos to expand their collection of California native plant photos and weed photos.

Tony Morosco also joined Calflora in 1997 to begin assembling a library of occurrence data on California plants from many sources, including botanists' checklists, regional floras and individual observations.

2000
In January of 2000 Ann Dennis, Tony Morosco, John Game, Emily Roberson, and Dean Taylor founded the public benefit corporation The Calflora Database to ensure the future of Calflora's services, and applied to the IRS for not-for-profit status. In 2001 the IRS granted Calflora status as a 501(c)(3) tax-exempt organization.

2003
In 2003 Calflora released its first online observation contribution system. Users were required to register in order to contribute observations. John Malpas joined Calflora in 2003 to work on various web applications. A priority for the team at this point was to be able to show the distribution of various wild plants, both natives and weeds, on the county level. Hosting for the Calflora website moved from UC Berkeley to Kattare, a private web services company.

2004: Herbarium Data
In 2004 Calflora entered into an agreement with the Santa Barbara Botanic Garden Herbarium to present their specimen database online. The inclusion of specimen data with other kinds of occurrence information was a big boost to Calflora's ability to show plant distribution. Calflora made similar agreements with other California herbaria, and by 2009 Calflora was hosting data from University and Jepson Herbaria (Berkeley), UC Riverside Herbarium, California Department of Food and Agriculture Herbarium, San Jose State University Herbarium, and the Santa Barbara Botanic Garden Herbarium. One of the benefits of this arrangement was to publicize the work being done by these institutions. Calflora users were able to download herbarium data directly from Calflora, the same way that they could download data from other sources.

2006-2008: New Applications
The first Calflora web applications allowed a user to 1. search for plants by name and other characteristics, or 2. search for the locations of particular plants. In 2006 Calflora released What Grows Here?, an application that enabled a user to move to a particular location on a map, and search for all plants that had been observed in that area.

In 2008, working with the Bay Area Early Detection Network (BAEDN), Calflora developed a streamlined application for entering plant observations utilizing Google Maps. Within a few years, individuals using this application became an important source of new observation data. In response to requests from contributors, Calflora added a Print Herbarium Label function to this application.

Also in 2008 Calflora developed v 1 of the eVegGuide application for NRCS California. The application allows NRCS clients to choose plants for a particular conservation purpose depending on their location in the state.

2010: CCH
In 2010 Calflora ended its direct relationship with various California herbaria, and instead entered into an agreement with the Consortium of California Herbaria (CCH). The promise of this agreement was that it would make it easier to keep the specimen data on Calflora up to date: each member herbarium would make the latest version of its own dataset available to the CCH, and the CCH would make datasets from all herbaria available to Calflora in a unified format. A condition of this agreement was that Calflora users would not be able to download CCH data directly from Calflora. This agreement continued until 2019.

2011: Cal-IPC
In 2011 the California Invasive Plant Council (Cal-IPC) embarked on an ambitious program to find out where invasive plants were growing in the state. They reached out to hundreds of agencies, community groups and local experts, asking for weed occurrence data. When they received data, they put it in Calflora -- over 200,000 records during a two year period. This data is now available to the public both through Calflora and through Cal-IPC's CalWeedMapper application. Cal-IPC continues to encourage local weed data collection efforts, and to support them with tools such as the Regional Priorities group on Calflora.

2012
In 2012 Calflora released the first phone application, Calflora Observer, for Android and iOS devices. Calflora also made groups available as a free service to registered users. A user can start a group for data collection purposes, and invite other users to join. Members of a group can see each others' unpublished observation records. In 2013 Cynthia Powell joined Calflora as GIS Project Manager. She became executive director in 2015.

Also in 2012 Calflora entered into an agreement with iNaturalist to display some research grade observations from iNaturalist on Calflora.

2014: Weed Manager
In 2014 Calflora released the Weed Manager system, a subscription service for agencies doing weed management. Calflora hired Darrell Anderson to develop a second generation phone application, Observer Pro, for Android devices. Using Observer Pro is a critical part of Weed Manager field work.

As of 2020, there are 35 Weed Manager groups, including the National Park Service, various State Parks districts, and various county agencies. Some of these groups maintain tens of thousands of weed observation records on Calfora.

2015: Plant Characteristics
Working with the NRCS, Calflora developed a system to model the environmental tolerances of various wild plants. The system tracks nine climate factors and six soil factors. All factors can be displayed as background layers on Calflora web applications that use Google Maps. Calflora released the Location Suitability application, which compares the tolerances of a particular plant with the factors at a particular location.

2017
Calflora hired Ed Dorrington to develop the Observer Pro phone application for Apple devices.

Calflora released v 4 of the NRCS eVegGuide, which uses plant characteritics modeling to suggest which plants will do well at a particular location.

Calflora released the Planting Guide application, which also uses plant characteristics modeling to suggest plants at a particular location -- for instance, for a restoration project or a native plant garden.

2019: Calinvasives
Working with Matteo Garbelotto at UC Berkeley, Calflora developed the Calinvasives online database to track plant pests and pathogens. As of 2020, the system has information on 128 pests.