knobthorn

Names and Synonyms

Common Names

• knobthorn
• Knob-Thorn
• Knobby Thorn
• Knobthorn Acacia

Scientific Names

Accepted name

Synonyms

• Acacia schliebenii
• Acacia brosigii
• Acacia nigrescens
• Acacia nigrescens var. pallens
• Acacia passargei
• Acacia passargei
• Acacia pallens
• Acacia perrottii
• Albizia lugardii

Regional and Traditional Names

Sources: Wikidata, Catalogue of Life

Taxonomical Classification

This plant belongs to the kingdom Plantae within the phylum Streptophyta and the class Equisetopsida. It is further classified under the subclass Magnoliidae and the order Fabales. Finally, it is a member of the Fabaceae family within the genus Senegalia.

Sources: The World Checklist of Vascular Plants (WCVP)

Distribution

This plant exhibits a diverse geographical distribution across several regions of the African continent. In East Tropical Africa, it can be found growing within the borders of Tanzania. Moving toward the southern regions, the species is well-established in the country of Angola. It is also commonly documented throughout South Tropical Africa in Malawi and Mozambique. Finally, its presence extends further into the southern reaches of the continent within Zambia.

Sources: The World Checklist of Vascular Plants (WCVP)

Botanical Identification

Ecology

The ecology of Senegalia nigrescens is characterized by its preference for deciduous bushland and wooded grassland environments, where it thrives particularly on black-soil areas. This species occupies a broad altitudinal spectrum, ranging from low-lying regions at an elevation of 25 m AMSL to higher terrains reaching a maximum of 1300 m AMSL.

Elevational range max:

1300 m AMSL

Elevational range min:

25 m AMSL

Habitat :

deciduous bushland and wooded grassland, especially on black-soil areas

Life history

The life history of Senegalia nigrescens is characterized by its nature as a perennial species, allowing it to persist in its environment over multiple growing seasons rather than completing its cycle within a single year. As a deciduous plant, it undergoes periodic leaf shedding, typically synchronized with seasonal changes or dry periods, which serves as an adaptive mechanism to manage water loss and conserve resources. This combination of a long-lived lifecycle and a deciduous habit enables the plant to endure fluctuating environmental conditions while maintaining structural stability within its ecosystem.

Deciduousness :

deciduous

Lifecycle :

perennial

Morphology

The morphology of Senegalia nigrescens is characterized by its robust growth form as a woody tree. This species is a self-supporting plant that grows independently, functioning neither as a parasite nor as an epiphyte, and maintains a strictly terrestrial habit. In terms of stature, it exhibits significant height variability, with individual plants ranging from a minimum of 2 m to a maximum height of 30 m, typically maintaining an average height of approximately 15 m.

Aquatic :

terrestrial

Climber :

self-supporting

Epiphyte :

terrestrial

Growth form :

tree

Parasite :

independent

Plant height max:

30 m

Plant height mean:

15 m

Plant height min:

2 m

Woodiness :

woody

Physiology

The physiology of Senegalia nigrescens is characterized by a C3 photosynthetic pathway, which dictates its carbon fixation processes and metabolic efficiency in its native environments. As a C3 plant, it utilizes the Calvin cycle to fix atmospheric carbon dioxide directly through the enzyme RuBisCO, a mechanism that typically requires careful regulation of stomatal conductance to balance gas exchange with transpirational water loss. Furthermore, this species is not a nitrogen fixer, meaning it does not possess a symbiotic relationship with nitrogen-fixing bacteria to convert atmospheric nitrogen into bioavailable forms; instead, it relies on the uptake of nitrogenous compounds directly from the soil through its root system to support its metabolic and structural development.

Nitrogen fixer :

no

Photosynthetic pathway :

C3

Reproduction

The reproduction of Senegalia nigrescens is characterized by the production of seeds with highly specific physical dimensions and weight profiles. The seeds exhibit a consistent seed volume, with both the maximum and minimum recorded values, as well as the mean volume, being precisely 200 mm³. In terms of mass, the seeds demonstrate a degree of variability; the seed mass ranges from a minimum of 0.14248 g to a maximum of 0.19608 g, resulting in an overall seed mass mean of 0.18083 g.

Seed mass max:

0.19608 g

Seed mass mean:

0.18083 g

Seed mass min:

0.14248 g

Seed volume max:

200 mm³

Sources: Global Inventory of Floras and Traits (GIFT)

Chemicals

Senegalia nigrescens has 7 reported phytochemicals identified across 0 scientific publications and several other databases. The most consistently reported chemicals include Flavonoids, Lupeol, Melanoxetin, Quercetin-3-O-methyl ether, STIGMASTEROL.

Flavonoids

1. Journal of ethnopharmacology

Lupeol

1. Journal of ethnopharmacology

Melanoxetin

1. Journal of ethnopharmacology

Quercetin-3-O-methyl ether

1. Journal of ethnopharmacology

STIGMASTEROL

1. Journal of ethnopharmacology

Tetracosan-1-ol

1. Journal of ethnopharmacology

quercetin

1. Journal of ethnopharmacology

Conditions

Senegalia nigrescens has 2 reported investigations on conditions identified across 0 scientific publications and several other databases. The most consistently reported conditions include convulsions, dysentery.

Convulsions

1. Journal of ethnopharmacology

Dysentery

1. Journal of ethnopharmacology