PlantLife Volume 50.6 December 2020. Kniphofia ichopensis var. aciformis

 

The curious case of a grass-like poker

 Text and photographs by Clinton Carbutt

Introduction

Red hot pokers of the genus Kniphofia Moench (Asphodelaceae) are well known amongst plant scientists, amateur botanists, horticulturalists and garden enthusiasts. Kniphofia is named after Johann Hieronymus Kniphof, an 18th-century German physician and botanist. It is a relatively large genus of approximately 73 species, almost entirely native to Africa, with two species in Madagascar and one in Yemen. The largest concentration of species occurs in South Africa, with a particular affinity for moist Afromontane grassland (Codd 2005; Ramdhani et al. 2006).

 

A Needle(-leaved Poker) in a haystack

Codd (1968) initially recognised the Ixopo Poker, Kniphofia ichopensis Baker ex Schinz, with no infra-specific taxa but later described a variety of K. ichopensis, namely Kniphofia ichopensis Baker ex Schinz var. aciformis Codd (Codd 1986). It is identical in floral characters to Kniphofia ichopensis Baker ex Schinz var. ichopensis Codd and was therefore considered to be a variety of K. ichopensis. However, Codd (2005) noted its unique leaves are worthy of further investigation and the variety may represent a separate species.

 

K. ichopensis var. aciformis is one of the more poorly known and interesting poker species. This elusive species is appropriately named the Needle-leaved Poker owing to its acicular (needle-like) leaves, which may also be referred to as ‘aciform’ (hence the variety name ‘aciformis’). This is in stark contrast to the soft, keeled and much broader leaves of the Ixopo Poker (Codd, 2005). The Needle-leaved Poker is therefore unlike any other poker and is easily overlooked when not in flower as it resembles a tufted grass.

 

I was delighted to encounter both the yellow- and white-flowered forms of this grass-like poker in their full splendour, which to the best of my knowledge have not been photographed before (Figures 1 & 2). These two collections in 2011 and 2017 have shed more light on the status of this species and provided a more comprehensive understanding of its geographical range and habitat preferences.

 

Figure 1. Photographic record of the Needle-leaved Poker (white-flowered form). A. Mature inflorescence showing the colour grading from deep orange (apex) to white (base); B. Young inflorescence in bud; C. Typical rocky grassland habitat (uMgano Nature Reserve); D. Roots and vegetative base; E. Herbarium specimen (Carbutt & Craigie 03 of 2011 NU). © Photos by C. Carbutt.

 

Figure 2. Photographic record of the Needle-leaved Poker (yellow-flowered form). A. Typical steep mountainous habitat dotted with small sandstone cliffs; B. & C. Inflorescences showing the canary-yellow flowers; D. Densely tufted base with grass-like leaves. © Photos by C. Carbutt.

 

Range and habitat ecology

The Needle-leaved Poker is a rare and cryptic species known only from the sub-escarpment foothills in south-western KwaZulu-Natal (Figure 3). It was first recorded from the Kamberg District (Farm Kilmore) by F.B. Wright in 1959 and later by M.A. Rennie from Mahaqwa Mountain near Bulwer in 1975 (Table 1). Two more recent gatherings in 2011 and 2017 by C. Carbutt and J. Craigie from uMgano Nature Reserve and the Kamberg District, respectively, have ended a 36 year collection hiatus (Table 1). The gathering by C. Carbutt and J. Craigie from uMgano Nature Reserve, located between Ntsikeni and Coleford Nature Reserves, is the southernmost for the species, some 75 km south of the type locality (Figure 3; Table 1). Only the Kamberg District specimens are of a canary-yellow colour form; those further south are of a white colour form (Figures 1-3; Table 1). The two colour forms therefore appear to be geographically isolated (allopatric). It will be interesting to find the geographical limit where the one colour form transitions to the other.

To date, the Needle-leaved Poker is known only from three sites (Kamberg, Mahwaqa and uMgano Districts) and is represented by six known gatherings (seven if a duplicate is included in this total) (Table 1). It is not a Drakensberg Mountain Centre endemic as outliers such as Mahwaqa Mountain and the Ntsikeni complex are not located within the Drakensberg Mountain Centre (Carbutt, 2019). Rather, it is more representative of the western limit of the Greater Midlands Centre of Plant Endemism (C. Carbutt, in preparation). 

Figure 3. Known records of distribution of the Needle-leaved Poker. Key to localities: KD, Kamberg District; MM, Mahaqwa Mountain; UNR, uMgano Nature Reserve. Localities are colour-coded to reflect the respective colour forms.

This species appears to be limited to the Sub-Escarpment Grassland Bioregion of the Grassland Biome, either in Drakensberg Foothill Moist Grassland (Mahwaqa Mountain and uMgano sites) or Mooi River Highland Grassland (Kamberg District). These vegetation types are classified as ‘Least Threatened’ and ‘Vulnerable’ respectively (Jewitt, 2018). This species is a habitat specialist, confined to steep slopes amongst rocky outcrops, or often at the base of small sandstone cliffs. Therefore, another important distinguishing feature separating the two varieties can be made on habitat preferences – the Needle-leaved Poker is confined to south-facing, steep rocky slopes in moist lower-montane grassland whereas the Ixopo Poker is confined mostly to grassy wetlands.

The Needle-leaved Poker occupies an elevation range from 1475–2050 m a.s.l. and flowers mostly in November (Table 1). This contrasts with the Ixopo Poker which extends in elevation to as low as 1000 m a.s.l. and flowers from December to March (Codd, 2005). The seed capsules of the Needle-leaved Poker mature some six weeks after flowering. It never seems to be abundant, with no more than four of five individuals noted at one spot. No pollinators were observed during field visits.

A perilous future?

The Needle-leaved Poker is Red Listed as ‘Data Deficient’ since it’s a poorly known species with insufficient information (Mtshali and von Staden, 2015). It was previously Red Listed by Scott-Shaw (1999) as ‘Lower Risk–Least Concern’.

Unfortunately this species is not well protected, occurring mostly on private farms. Only the community-owned uMgano Nature Reserve proclaimed in 2018 through the Biodiversity Stewardship mechanism affords the species some formal protection. Fortunately, however, its preference for steep slopes and rocky enclaves largely precludes the threat of livestock grazing and trampling.

A reappraisal of its IUCN Red Data status is required, which will most likely be ‘Vulnerable’ based on its restricted geographical range, relatively small population size, poor levels of protection and risk of population decline through habitat loss. Further searches will hopefully locate new populations in suitable habitat and help craft a more accurate understanding of this elusive and enigmatic grass-like poker. This quirky variety of K. ichopensis is currently subject to a study which may result in affording it specific rank. 

 

Table 1. Known gatherings of the Needle-leaved Poker listed in chronological order. All known specimens were consulted in the National Herbarium (PRE), Bews Herbarium (NU) and Ward Herbarium (UDW). UDW has since been incorporated in to NU.

References

Carbutt, C. 2019. The Drakensberg Mountain Centre: A necessary revision of southern Africa’s high-elevation centre of plant endemism. South African Journal of Botany 124: 508-529. https://doi.org/10.1016/j.sajb.2019.05.032.

Codd, L.E. 1968. The South African species of Kniphofia. Bothalia 9(3&4): 363-513.

Codd, L.E. 1986. Liliaceae: Notes on Kniphofia. Bothalia 16: 231-232.

Codd, L.E. 2005. Kniphofia. In: Flora of Southern Africa, eds. Germishuizen, G. & Momberg, B.A., Vol. 5, Part 1, Fascicle 2 (Asphodelaceae, first part), pp. 1-94. South African National Biodiversity Institute, Pretoria.

Jewitt, D. 2018. Vegetation type conservation targets, status and level of protection in KwaZulu-Natal in 2016. Bothalia 48(1), a2294. https://doi.org/10.4102/ abc.v48i1.2294.

Mtshali, H. & von Staden, L. 2015. Kniphofia ichopensis Baker ex Schinz var. aciformis Codd. National Assessment: Red List of South African Plants version 2020.1. Accessed on 2020/11/25.

Ramdhani, S., Barker, N.P. & Baijnath, H. 2006. Phylogenetics of the genus Kniphofia Moench (Asphodelaceae). In: Taxonomy and ecology of African plants: their conservation and sustainable use (Proceedings of the 17th AETFAT Congress), eds. Ghazanfar, S.A. & Beentje, H.J., pp. 559-573. Royal Botanic Gardens, Kew.

Scott-Shaw, C.R. 1999. Rare and threatened plants of KwaZulu-Natal and neighbouring regions. KwaZulu-Natal Nature Conservation Service, Pietermaritzburg.

About the author: Clinton Carbutt is the Plant Scientist for Ezemvelo KZN Wildlife with an interest in the floras of the Drakensberg Mountain Centre and KwaZulu-Natal Midlands, as well as the conservation of temperate grasslands. He is passionate about mountains and mountain floras. He has a PhD in Botany from the University of Natal and is the Southern African representative on the IUCN Mountains Specialist Group.