PlantLife Volume 51.4 July 2021. A second population of the Ixopo Everlasting (Helichrysum citricephalum)

 

A Second Population of the Ixopo Everlasting 

(Helichrysum citricephalum: Asteraceae)

 

Text and photographs by Clinton Carbutt

 

 

Introduction

Helichrysum Mill. (Asteraceae) is a taxonomically challenging genus. Firstly, it is mega-diverse, consisting of approximately 600 species of herbs and shrubs spread across Africa, Madagascar, Eurasia and Australasia (Wilson 1992; Beentje 2000). South Africa is clearly the stronghold for the genus, accounting for about 245 species (Hilliard 1983; Grieve 2020). Secondly, it is taxonomically labile. Relationships between Helichrysum species and with closely related genera are neither fully understood nor satisfactorily resolved and therefore await more robust circumscription. The genus has been viewed as a dumping ground with many of its former species now reclassified and assigned to smaller genera. Some go as far as calling it a controversial genus considered artificial and probably polyphyletic and paraphyletic (Anderberg 1991). For example, its presence in Australasia is tenuous. Five species, not closely affiliated with the African and Mediterranean Group, are known from Australia (Jeanes 1999) but may be reclassified to other genera (Ohlsen 2016). Thirdly, many species bear a superficial resemblance to one another and are therefore difficult to tell apart.

 

One of the more obscure South African Helichrysum species became known to me during a literature search for a study I am undertaking on the endemic plants of the greater Midlands region. Although I had not visited the site, I knew of the type locality but wanted to search a little more broadly in the hope that I may find another population. And so a field trip was soon conceived and executed. It was a warm late summer’s morning. I was trudging up a grassy slope outside Ixopo intent on seeking out this rare everlasting known only from its type locality just less than 10 km south-west of my position. As I crested the slope I noticed a faint line of large grey shrubs with bright yellow flowering heads in the distance. In the pit of my stomach I knew it was my target species, the enigmatic Ixopo Everlasting. 

 

The Ixopo Everlasting

The Ixopo Everlasting, Helichrysum citricephalum Hilliard & B.L.Burtt, is a relatively large (up to 1 m tall) robust shrub with sessile, silver-grey felted leaves and bright lemon-yellow flowering heads, hence Hilliard and Burtt (1976) assigning the species epithet H. citricephalum. Fortunately, due to this unique combination of facies it bears no resemblance to any other of the South African Helichrysum species and is therefore very easy to identify in the field (Figures 1 & 2).

 

Figure 1. The bright lemon-yellow heads and felted silver-grey leaves characteristic of H. citricephalum.

Figure 2. The robust, shrubby growth habit of H. citricephalum.

 

Type Collection

H. citricephalum was hitherto known only from the type collection made by Olive Hilliard and Bill Burtt in the 1970s between Ixopo and Umzimkulu and one made by Krook at the same locality in the late 1800s (Hilliard 1983). The site is described as “steep moist shady banks of a roadside cutting” (Hilliard 1977; p. 249). Hilliard (1977) speculated that due to the coarse and scrubby nature of the vegetation on site that “probably its natural habitat is forest margin scrub”. To the best of my knowledge it has never been found along forest-grassland ecotones, but its affinity for dense, scrubby vegetation may certainly lend itself to that microenvironment.

 

Second Population

Habitat, estimated population size and phenology

Unlike Hilliard and Burtt’s (1976) type locality description, this second population is growing above and along three, short first-order drainage lines, all contained within a small catchment on cool, south-facing slopes (Figures 3 & 4). Individuals are not directly associated with the drainage lines and therefore not part of the riparian vegetation. No doubt the drainage lines and the cordon of riparian vegetation afford some degree of fire protection. Individuals rapidly thin out in the more flammable grassland upslope and are unlikely to thrive in short, open grassland. 

 

 

Figure 3. Proximal view of a drainage line with scattered grey shrubs of H. citricephalum growing along its upper bank.

 

Figure 4. Distal view of the drainage lines along which H. citricephalum occurs.

Similar to the type locality, individuals favour dense, rank vegetation (Figures 5 & 6). Other members of this community include Hyparrhenia sp. (Poaceae), Inulanthera dregeana (Asteraceae), Miscanthus ecklonii (Poaceae), Pteridium aquilinum subsp. aquilinum (Dennstaedtiaceae), Pterygodium magnum (Orchidaceae), Rabdosiella calycina (Lamiaceae), Setaria sp. (Poaceae), Syncolostemon densiflorus (Lamiaceae) and Xysmalobium orbiculare (Apocynaceae). At a vegetation type level, this species is confined to Midlands Mistbelt Grassland, classified by Jewitt (2018) as an ‘Endangered’ grassland type in the Sub-escarpment Grassland Bioregion of the Grassland Biome. The size of the mistbelt grassland patch was 1 km² but far less of this area was suitable habitat. 

 

 

Figure 5. H. citricephalum typically growing in coarse, rank vegetation.

 

Figure 6. Steep scrubby slope with clumps of H. citricephalum leading down to a drainage line.

The estimated size of the population is 300–350 individuals, the largest known to date. However, ascertaining an accurate count was sometimes difficult as this species has a tendency to form dense clumps in places making individuals difficult to distinguish from one another (Figures 6 & 7). A large proportion were not in flower, inferring that the population does not flower synchronously. Many individuals, or a portion of an individual, had completely dried out. The dried leaves are retained (Figure 8). Two trips to the site revealed a flowering phenology from late summer through early autumn (February–March). This underscores the importance of late season botanising when certain taxa bloom well after the midseason peak. 

 

 

Figure 7. A dense clump of H. citricephalum making the counting of individuals occasionally challenging.

 

Figure 8. Example of a non-flowering individual of H. citricephalum showing dead stems and dried, retained leaves.

Distribution and elevation

This species is a KwaZulu-Natal Midlands endemic, confined to a very small area in southern KZN south-west of Ixopo towards Umzimkulu. The second population is located approximately seven kilometres from the type locality, closer to Ixopo. Here it is confined to an elevation range of ca. 1070–1150 m a.s.l. Scott-Shaw (1999) records its elevation range as 1200–1300 m a.s.l. (making reference to the type locality) and unfortunately Hilliard does not mention elevation in any of the species’ treatise. Its global distribution is most likely confined between Ixopo and Umzimkulu, in rank scrubby vegetation bordering drainage lines, or forest margin ecotones and rocky areas offering shelter from frequent fires.

 

Phytogeographical Affinities

Very interestingly, H. citricephalum is not closely related to any South African Helichrysum species but is allied to two similar looking species with more tropical affinities, namely H. kirkii var. petersii and H. buchananii (Hilliard and Burtt 1976; Hilliard 1977). Both species occur in the highlands of south-central and tropical east Africa in montane grassland between 850–2850 m a.s.l. and 1750–2500 m a.s.l. respectively (Beentje 2000; Beentje et al. 2005). These three closely affiliated taxa form part of the Afromontane element, a floristic assemblage of plant taxa co-occurring in the grassy component of the montane mosaics of sub-Saharan Africa (see White 1978).

 

Conservation Status

H. citricephalum was originally described as being “numerous” and “found in quantity” at the roadside cutting (Hilliard and Burtt 1976; Hilliard, 1977). It is astounding to note that Hilliard (1983) a little more than five years later mentioned that “the only known locality has been destroyed by road widening”. Scott-Shaw (1999) noted that the population had not been relocated and somewhat surprisingly Red Listed the species as ‘Endangered’. Scott-Shaw was later able to relocate the type locality, and echoed Hilliard’s concerns that road widening had impacted on the population. Scott-Shaw (2011) noted fewer than 200 individuals growing away from the road in close proximity to an informal settlement with ongoing site expansion and degradation (as this was 10 years ago I expect the number to be far fewer now). Therefore, Scott-Shaw et al. (2011) assessed H. citricephalum as ‘Critically Endangered’ (CR) under criteria B1ab (i, ii, iii, iv, v) (IUCN 2012), implying that this species is facing an extremely high risk of extinction in the wild. Despite a known second population, it appears that H. citricephalum will remain CR given that both populations occur within 100 km² and are highly fragmented when assessed against the IUCN (2012) adjudication criteria. This population is the largest known of its kind and is the stronghold for the species, thriving in an almost pristine grassland environment. Although tenuously secure, this population is significant not only due to its size but because the type population is in bad shape and unprotected. It also occupies previously unrecorded habitat along the upper banks of drainage lines, offering renewed hope for the location of more populations in similar habitats. A Google Earth survey of the landscape between Ixopo and Umzimkulu unfortunately makes for depressing viewing as very little native vegetation remains. Only small pockets of Eastern Mistbelt Forest and Midlands Mistbelt Grassland are visible within a matrix of forestry plantations and dairy pastures. Hopefully more populations are persisting in these remaining small remnants where remarkable stores of biodiversity are clinging to life. This fate is shared with temperate grasslands across South Africa (Carbutt et al. 2010) and the world (Carbutt et al. 2016).

 

Concluding Remarks

This species epitomizes the plight of many highly range-restricted plant species that have little to no formal protection. No legal instruments, whether area-based (such as the Protected Areas Act or Biodiversity Stewardship contractual agreements) or species-based (such as ToPS or the KZN Nature Conservation Ordinance) offer this species any form of meaningful protection. The second population is currently secure but only because the land-use appears secure and is loosely managed in a way that is coincidentally compatible with this species. The property is a prime candidate for Biodiversity Stewardship.

 

Hopefully its name, the Ixopo Everlasting, will ring true prophetically and the species will survive in perpetuity. This species is in urgent need of an autecological study to understand its biology, particularly breeding system dynamics such as dispersibility, fecundity and longevity. A long-term monitoring programme should be established with recommendations for management. Searches for further populations to more accurately ascertain the range and total population size of the species need to be undertaken in concert with land owner engagement and awareness creation. An appeal is made to a university student to tackle this as an Honours or Masters project.

 

  

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.

 

References

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Carbutt C, Tau M, Stephens A, Escott B. 2011. The conservation status of temperate grasslands in southern Africa. Grassroots 11(1): 17–23.

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