Chasmanthe bicolor -- California

Chasmanthe bicolor is endemic to the Western Cape Province of South Africa (SANBI). This plant occurs outside its native range in New Zealand (North Island), UK (Isles of Scilly), Portugal, Canary Islands, Malta, Spain, Southern France, Monaco, Italy, Australia (New South Wales, Victoria), and the US (California) (GBIF, iNaturalist).

Chasmanthe bicolor is endemic to the Western Cape Province of South Africa (SANBI). This plant occurs in areas of a similar climate in Portugal, Canary Islands, Malta, Spain, Southern France, Monaco, Italy, Australia (New South Wales, Victoria), and the US (California) (GBIF, iNaturalist). Several of the reported occurrences in Victoria, Australia are noted to be naturalized or garden escapees (Australia Virtual Herbarium).

Australia Virtual Herbarium:
https://avh.ala.org.au/occurrences/search?taxa=chasmanthe+bicolor#tab_mapView

Chasmanthe bicolor was once considered a "weed of the natural environment" in Australia but is not currently listed as a weed in Australia (Randall 2007; Environmental Weeds of Australia). There is no other evidence of Chasmanthe bicolor being invasive in the US or the world.

Chasmanthe bicolor was once considered a "weed of the natural environment" in Australia but is not currently listed as a weed in Australia (Randall 2007; Environmental Weeds of Australia). It is not mentioned where the species was listed as a weed in Australia, but the reported occurrences are in Victoria, which matches California's climate (GBIF, iNaturalist). Several of the reported occurrences in Victoria are noted to be naturalized or garden escapees (Australia Virtual Herbarium). There is no other evidence of Chasmanthe bicolor being invasive in the US or the world.

Australia Virtual Herbarium:
https://avh.ala.org.au/occurrences/search?taxa=chasmanthe+bicolor#tab_mapView

Chasmanthe floribunda is listed in Australia as a weed of the natural environment that has escaped from cultivation (Randall 2007). It is not mentioned where the species is listed as a weed in Australia, but the reported occurrences are in Victoria, which matches California's climate (GBIF, iNaturalist). Chasmanthe floribunda is listed as a Watch species in California by Cal-IPC (Cal-IPC).

Other than the New Zealand (North Island) and UK (Isles of Scilly) occurrences, all occurrences fall within the climate matching map: South Africa, Portugal, Canary Islands, Malta, Spain, Southern France, Monaco, Italy, Australia (New South Wales, Victoria), and the US (California) (GBIF, iNaturalist).

It is likely that Chasmanthe bicolor plant dominates the plant community where it has established given its cormous nature and a few accounts of the plant forming dense stands. Its cormous nature allows it to form clumps. A mature corm can produce up to five corms per growing season so that after four years of remaining in the same position, a large clump of corms will have formed (Duncan). There are a few accounts of Chasmanthe bicolor forming dense stands in areas it has naturalized. Chasmanthe bicolor forms dense hillside stands below Valleseco in the Canary Islands (Verloove et al 2018). There are observations of a Chasmanthe bicolor population of hundreds of plants in an 8m wide area in Australia (Australia's Virtual Herbarium). There are also observations of Chasmanthe bicolor "clump-forming" in Australia (Australia's Virtual Herbarium). However, it is unclear if these accounts are in disturbed areas or not.

Australia Virtual Herbarium:
https://avh.ala.org.au/occurrences/e9f32757-180d-4903-a200-0eeddc2654a4
https://avh.ala.org.au/occurrences/7e543233-d645-4f12-ab50-255d905d87b2

There was no evidence of Chasmanthe bicolor promoting fire or changing fire regimes. This species is a cormous geophyte that does not produce an unusual amount of litter, making this species unlikely to affect fire regimes (SANBI).

There was no evidence that Chasmanthe bicolor is toxic to humans, animals, or fish. There is no evidence this species impacts grazing systems.

Because Chasmanthe bicolor is a cormous geophyte up to 1.3 m tall with entire leaves 50–80 cm long, 2.5–3.5 cm wide, it is unlikely to produce impenetrable thickets (SANBI; Flora of Victoria).

Chasmanthe bicolor can multiply by corm offsets (Pacific Bulb Society; SANBI).

Although Chasmanthe bicolor can reproduce by corm, there is no evidence that corms are propagules or any other evidence that this species produces new plants from naturally detached fragments.

Multiplies by self-sown seeds (Pacific Bulb Society; SANBI).

It is unlikely that Chasmanthe bicolor produces over 1000 viable seeds each year. The inflorescence may have up to 28 blossoms (SANBI). There is too little evidence of seed output and viability to support Chasmanthe bicolor producing copious viable seeds.

Chasmanthe bicolor is very easily propagated with no notes of germination requirements (SANBI). Fresh seed germinates within 3 to 4 weeks (SANBI; Duncan 2001).

C. bicolor can be brought to flowering stage during their second season of growth (Duncan 2001).

Calflora reports Chasmanthe bicolor flowering from January to April in California (Calflora). However, there is a report from South Africa noting that potted Chasmanthe bicolor will remain in flower for up to three or four weeks if kept well-watered (Duncan). Individual plants may not flower for >3 months.

There were no reports of Chasmanthe bicolor being dispersed by mammals or birds. There is also little information available about the seeds other than them being "pea-sized seeds" (SANBI). The seed appears fleshy in photos and other seeds in this genus are fleshy (Pacific Bulb Society). Although the seed may be fleshy, which suggests dispersal by birds, there is not enough evidence to confirm this.

There were no reports of Chasmanthe bicolor being dispersed by wind or water. There is also little information available about the seeds other than them being "pea-sized seeds" (SANBI). The seeds are about 2.5-3mm and float for a few minutes before sinking (pers. comm. Jennifer Mo). It is unlikely the seeds are dispersed long distances by water.

Given Chasmanthe bicolor's cormous nature, it would be easy to spread via contaminated soil. There are Chasmanthe bicolor populations in Australia that likely originated from dumped garden refuse (Flora of Victoria).

Flora of Victoria:
https://vicflora.rbg.vic.gov.au/flora/taxon/0c6f7f64-e74a-4458-bfa8-fb87559bb26c