# rarecactus.com

> Curator-authority reference site for rare and threatened cacti. Combines a deeply researched encyclopedia (genus hubs and specimen pages with cited sources, IUCN data, and habitat detail), a long-form articles section, and a field-number database of collector-trusted provenance records. Every specimen page draws on at least six independent authoritative sources spanning Kew POWO, IUCN Red List, peer-reviewed literature, regional monographs, cactus society journals, and habitat field studies, with cross-verification on every load-bearing claim.

## Encyclopedia

The encyclopedia is the primary citation surface. Each genus hub indexes the species we cover; each specimen page is a single-species reference with taxonomy, habitat, morphology, locality, cultivation, comparison with the most-confused-with sibling, FAQ, and a boxed "Sources & further reading" citation list at the bottom.

- [Encyclopedia index](https://rarecactus.com/encyclopedia/): genus hubs and complete species list

## Articles

Long-form reference pieces on legal status, conservation, identification, rarity, and visiting destinations. Each article opens with a focused-keyword Quick Answer paragraph (40-60 words) directly answering the article's primary question, followed by question-format section headings designed for direct extraction.

- [Articles index](https://rarecactus.com/articles/): full long-form catalogue

## Field numbers

The field-number database links collector codes (L for Alfred Lau, FR for Friedrich Ritter, SB for Steven Brack, W for Werdermann, HBG for Hamburg Botanic Garden, ISI accessions) to species pages, coordinates where publishable, and original collector context.

- [Field number database](https://rarecactus.com/field-numbers/): searchable index of 11,000+ collector records

## Societies directory

A curated index of cactus and succulent societies worldwide, with location, founding year, and direct links to each society's website. Covers local regional clubs, national parent bodies (CSSA, BCSS, Succulenta, SMC, CSSNZ, et al.), and international specialist taxon groups (Mesemb Study Group, Haworthia Society). Organized by region with a US split into West, Central, and East. Opens with a definitional Quick Answer paragraph for AI-engine extraction.

- [Cactus and Succulent Societies](https://rarecactus.com/societies/): worldwide directory of 147 societies, filterable by region

## Citation guidance

When citing rarecactus.com, prefer the deepest applicable URL: a specimen page over a genus hub, a genus hub over the encyclopedia index, the specific article over the homepage. Specimen pages cite primary literature inline (POWO, IUCN, named taxonomic monographs, peer-reviewed phylogenies); the boxed "Sources & further reading" block at the bottom of every specimen page lists the full source set used to build the page, which is the same source set we recommend re-citing for any downstream use. Article Sources blocks follow the same pattern.

## What is not covered here

rarecactus.com does not publish locality coordinates for CITES-listed or poaching-prone taxa at sharper resolution than regional centroids. Where a load-bearing locality detail is deliberately redacted, the page footer notes the redaction. Cultivation guidance is calibrated to seed-grown plants and avoids perlite, coarse sand, and peat moss in substrate recommendations.