This study provides a descriptive treatment and documents the population structure of
All accessible populations were surveyed and documented, and eight transects were randomly placed to gather data on size-class distributions.
The population structure analyses of
The Flora of Southern Africa (FSA) comprises more than 30 000 plant species with 60% endemism (Van Wyk & Smith
Amongst the taxonomic treatments of South African palms were those in ‘Flora Capensis’ (Wright
The first mention of
Research on South African palms has generally been very limited, and the uncertainty regarding the origin of
Distribution records were obtained from the National Herbarium in Pretoria (PRE) and A.P. Goossens Herbarium (PUC). Further locality records were obtained from field visits in October 2016 and 31 points were logged (
(a) Distribution of
Eight transects of 100 m were randomly placed. Plants up to 4 m height were measured with a measuring stick and those with heights above 4 m were determined by using a clinometer. Height class distributions were compiled. Sturge’s rule was applied to determine the size-class distribution and frequency intervals for the population graphs (Scott
Stems solitary, 20 m – 25 m tall, straight, with conspicuous swelling half way up the stem (
The palm has varied uses in Africa (Ali et al.
The palm is distributed along floodplains on sandy, well-drained alluvial soils of the Selati River near Leydsdorp in Limpopo province (
Flowers and fruits are produced throughout the year (Orwa et al.
Field observations confirmed the findings of Dyer (
Mature plants in the Leydsdorp area drop their leaf bases at approximately 8 m height (7 m according to Coates Palgrave [2002]), form a swelling on the trunk and then flower for the first time. We estimate the age of maturity for these specimens at approximately 47–53 years, which is in accordance with Dalziel (
It is generally accepted that the fruits are eaten by elephants and in this way, the seeds are distributed (Orwa et al.
The alternative view for the disjunction is that the palm is an introduced species (Dyer
It is also worth considering that
1A. Leaves costa-palmate..............................................2
1B. Leaves pinnate....................................................4
2A. Stem to 25 m tall; leaves 3 m – 4 m long; fruit 7 cm – 17 cm in diameter, yellow to orange brown when mature........................................
2B. Stem to 7 m tall; leaves 1.5 m – 2.0 m long; fruits 4 cm – 5 cm in diameter, reddish brown when mature.......3
3A. Fruit ovate to pear-shaped and ridged, with distinctly narrow base; stems up to 5 m tall; multi-stemmed; mainly a coastal distribution................................
3B. Fruit globose-oblong, without ridges; stems up to 7 m tall; usually solitary; associated with the drier interior....................................
4A. Single stemmed; leaves 6 m – 10 m long, hooked spines on the margin of leaflets; fruit covered with overlapping scales........................................
4B. Multi-stemmed; leaves less than 6 m long, margin of leaflet entire or crenulate; fruits smooth...........................5
5A. Petiole without spines; leaves up to 6 m long, silvery blue-green at a distance, bright green nearby, pinna reduplicate, margin entire; monoecious; fruit round, 20 mm in diameter; restricted in distribution to northern banks of Msikaba and Mtentu rivers, Pondoland..............................
5B. Petiole with long, sharp spines at the base; leaves up to 4 m long, light to dark green, induplicately pinnate, margin minutely crenulate; dioecious; fruit ovate, 15 mm in diameter; widely distributed throughout tropical and subtropical Africa................................................
In the Leydsdorp region, the populations are associated with other Lowveld tree species such as
A total of 614 plants were recorded in the Leydsdorp area (
Height classes (m) and quotient analyses (solid black line) of
Number of individuals per life stage as recorded for
Life stage | Individuals |
---|---|
Mature male | 86 |
Mature female | 110 |
Juveniles | 264 |
Sub-juveniles | 154 |
Total | 614 |
Note: The number of dead adults was 8.
The population has an SDI value slightly above 0.1 (i.e. 0.18), which reveals that size frequency is not steeper than what would be expected from an exponentially declining population. This is an indication that individuals are evenly distributed amongst the size classes, but this needs to be considered with PI values that are based on the assumption that an ideal undisturbed population should represent a monotonic decline (PI = 0). This was, however, not typical for
The occurrence of
SOUTH AFRICA. LIMPOPO. – 2231 (Messina): At the confluence of the Luvuhu and Limpopo rivers, Pafuri, (–DD), 12 April 2014,
Mr Hardus Cloete is thanked for his assistance with fieldwork. Mr Scott van Eden provided the distribution maps. Prof. Braam van Wyk and Dr Hugh Glen are thanked for valuable discussions on the topic and for providing locality data. The Pretoria National Herbarium and Skukuza Herbarium are acknowledged for providing access to study material. The key was tested by field botanists in South Africa.
The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.
S.J.S. planned and coordinated the study and wrote the article. M.S. contributed to the writing of the article and was responsible for the taxonomic treatment and construction of the key.
Funding for this study was provided by the North-West University.