Bergia capensis
(white water fire)

Bergia capensis is a small annual herb which grows in wet places and is native to Africa, southern China and tropical Asia. It has been introduced, probably (although no details are available) unintentionally through the cultivation and trade of rice, in Europe, Central America, Mexico and the Caribbean. Although it grows in rice fields, no information is available about possible impacts on rice crops, and there are only limited reports of its being invasive anywhere.

Bergia capensis is native to tropical and subtropical areas in Africa and from China (Guangdong) to tropical Asia (WCSP, 2019). It is reported as introduced in Central America (Costa Rica), the West Indies (Cuba, Haiti, Netherlands Antilles), southwestern Mexico, South America (Ecuador, Peru, Venezuela) and Europe (Greece, Portugal, Spain); see Distribution Table for details (Gálvez, 2019; Greuter and Raus, 2001; Encyclopedia of Life, 2019; Missouri Botanical Garden, 2019; WCSP, 2019).

Acevedo-Rodríguez and Strong (2012) report the species as native to Cuba and Hispaniola, but other sources disagree with this. According to Flora of Nicaragua (2019), it is not recorded as present in that country, but is to be expected in areas of lower elevation as it is present in neighbouring Costa Rica. Publications by Svenson (1946a, 1946b)  do not prove that the species is present in Peru as they record it from the coast of Ecuador and Peru “in pools south of Ancón”, which is a locality name used at both countries; but Missouri Botanical Garden (2019) does not appear to be in doubt about its presence in Peru.

As for where Bergia capensis is invasive, there is limited information available. Oviedo Prieto et al. (2012) report it with few details as invasive in Cuba, as a naturalized species with a tendency to proliferate at various localities in the country. They also say that it is invasive in Europe, using DAISIE as a reference, but the information at DAISIE (2019) is that it has an alien/unknown status in Greece and in Spain it is an alien/established species. Greuter and Raus (2001) report that its degree of naturalization in Greece is unknown and that it is only naturalized in rice fields in the east of Spain. As it has been present in the New World since the mid-19^th century, it could be considered that if invasive it would have been more widespread and abundant there by now. According to Leach (1989), Bergia species are not more widespread in suitable areas of Australia as they do not compete well with other wetland species. Nevertheless, the distribution of B. capensis might be under-reported, as small species associated with wetlands are usually under-collected and/or overlooked. For example, Milne-Redhead (1948) reports that the Royal Botanic Gardens, Kew, only received two collections of B. capensis in eighty years.

There is limited information available to properly assess the risk of introduction of Bergia capensis. It should be considered as being at low to medium risk of introduction, mainly because of its possible introduction and spread through rice cultivation. In most of the countries where it is reported as present and naturalized there is no information about its abundance and spread.

B. capensis is reported as occurring in paddy fields, grasslands, rice fields, irrigation channels, ditch sides, rock pools, marshes, muddy places and along streams (Jacobsen, 1973; Trama et al., 2009; Encyclopedia of Life, 2019; Quiles Hoyo, 2019; India Biodiversity Portal, 2019).

Several species of Bergia are weeds of rice fields (Tucker, 1986). Bergia capensis is reported as occurring in rice fields (Smythies, 1984-1986; Encyclopedia of Life, 2019; Flora of Greece web, 2019; New York Botanical Garden, 2019). No information about the possible impact on the rice crops is given.

Genetics

The chromosome number reported for Bergia capensis is 2n=18 (Tucker, 1986).

Reproductive Biology

Very little information is available on the reproductive biology of Bergia capensis.  According to East (1940), self-fertilization is common in Bergia.  At the India Biodiversity Portal (2019), B. capensis is reported as being self-pollinated, cross pollinated and visited by insects. Seed dispersal is by autochory (self-dispersal), anemochory (wind dispersal) and zoochory (birds or animals).

Physiology and Phenology

The species flowers from January to February and in May in Africa (E-Flora of South Africa, 2019); it flowers and fruits from August to November in India (India Biodiversity Portal, 2019).

The presence of phenolic acids, including delphinidin, ellagic acid, quercetin, cyanidin and kaempferol, is reported from members of the genus Bergia (Tucker, 1986). Saponins and alkaloids are absent from the genus.

Longevity

B. capensis is a small annual herb (WCSP, 2019).

Environmental Requirements

Little information about the environmental requirements of Bergia capensis is available, other than that it grows in seasonally inundated areas (Tucker, 1986; India Biodiversity Portal, 2019). Leach (1989) reports that Bergia can survive high salinity, high temperatures and droughts, but does not specify which species.

The species of Bergia are susceptible to various insect pests, powdery mildews, nematodes and moulds (India Biodiversity Portal, 2019). The fungus Podosphaera xanthii [Podosphaera fusca] is reported as growing on the leaves of Bergia capensis in Europe (Ellis, 2019).

General

• Ritual uses

Medicinal, pharmaceutical

• Traditional/folklore
• Veterinary

The two genera in the Elatinideae family can be distinguished by Elatine having membranous sepals and capsules, while Bergia has herbaceous sepals and crustaceous capsules (Leach, 1989). Bergia capensis is similar to B. ammannioides, both being among the more widespread species in the genus. B. capensis stems are erect, thick, fleshy and glabrous; with leaves short petiolate; flowers and stipules glabrous; and fruits 0.5 mm long.  B. ammannioides has slender, glandular-pubescent, somewhat woody decumbent stems; with leaves sessile or nearly so and glandular beneath; flowers and stipules pilose; and fruits 0.3 mm long (Russell, 1977; India Biodiversity Portal; 2019).

Information about the biology of B. capensis, its environmental requirements and its possible impact on other species is needed.

08/09/19: Original text by:

Jeanine Vélez-Gavilán, Universidad de Puerto Rico, Puerto Rico