Friis I. et al. 2017. Kalanchoe hypseloleuce (Crassulaceae), a new species from eastern Ethiopia, with notes on its habitat. Kew Bulletin 72:30. DOI 10.1007/S12225-017-9704-7
- The available data allows us to assess the species under criterion B of the IUCN Red List system. The extent of occurrence (EOO) based on our observations (specimens and sight records, listed in Table 1) is 817 km2, which is far below the threshold of 5000 km2 for Endangered (EN). The corresponding area of occupancy (AOO) is 16 km2, with a cell width of 2 km as recommended by IUCN (2012); this is also below the threshold for EN (<500 km2). Both calculations were carried out with the online conservation assessment tool GeoCAT (Bachman et al. 2011). Furthermore, we ran a climate envelope model (see last paragraph of ‘A new species of Kalanchoe in this habitat') to predict areas of suitable climatic conditions for Kalanchoe hypseloleuce (Map 2). From the resulting map, we selected additional coordinates (listed in Table 1) to run the EOO and AOO calculations again. The new EOO is 7712 km2 and the AOO is 64 km2 (with the default cell width of 2 km). These values are below the thresholds for Vulnerable (VU) and Endangered (EN) respectively. The AOO requires a minimum sample size of 125 locations scattered at intervals of 2 km or more in order to get a result above the threshold for EN (500 km2). We therefore deem the EOO calculation to be more reliable for the assessment. Observations on the western-most location (E Arsi): We observed Kalanchoe hypseloleuce only after the abundant rains in November, 2015; not during our visit in the dry November of 2014. We saw the species in three different sites, at 3.6 and 4.5 km distance from each other. In all three sites, it occurred in groups of two to four individuals, all flowering approximately at the same time. We assume that the species is monocarpic (see discussion in ‘Notes') and germinates under suitable climatic conditions from seeds in the soil seed bank. We assume it does not benefit from moderate disturbance since there were other sites of more disturbed open bushland north-east of the Scianan River and the village of Remiti (Map 2) where we would have expected the species to occur, but we didn't see it. At present, there is no formal protection of the location in E Arsi, nor is there any significant human influence. Large areas around the location were sparsely inhabited or not at all. The vegetation seemed uniform on the flat limestone-areas between the gorges of the Elele and the Scianan Rivers, a distance of c. 20 km. No village could be seen from the road for a distance of approximately 30 km (the village Seru in Arsi is c. 40 km to the SW, at 1650 m a.s.l., Sheik Hussein in Bale is c. 30 km to the S, at 1350 m a.s.l., and Remiti, also called Bui, in W Harerghe is c. 20 km to the N, at 1500 m a.s.l.; see Map 2). In E Arsi, nomadic Oromos do use the vegetation for grazing camels. We saw only a few camels N of the Elele River, mostly a few animals left to graze by themselves, and flocks of sheep and cows only between the Elele and Wabe Shebele Rivers. We did not meet any herdsmen along this stretch of road between Elele and Scianan. We conclude that currently, the grazing in the area doesn't present a threat to the flora. Observations on the eastern-most location (E Harerghe): The situation is different at the location in E Harerghe, where Burger 3569 was collected, nearly 250 km east of our observed locations in the west. That location now falls within the formally protected Babile Elephant Sanctuary, but protection of this conservation area is inadequate. Vegetation and wildlife in this region are declining (MesfinSeifu &Fekadu Beyene2014), and plant and animal species are under pressure. Observations on the modelled intermediate locations: We assume that the species occurs in the locations predicted by the climate envelope model between the observed locations in E Arsi and the population in E Harerghe (Map 2,Table1). There is an unexplained gap of nearly 150 km between the eastern-most population in E Harerghe and the model prediction. From what we can see on Google Earth (2016), some of the predicted locations are intensely farmed and comparatively densely populated, although not accessible by road. Others look almost completely uninhabited, like the observed locations in E Arsi. We have not observed a decline in the quality or extent of the habitat in E Arsi, but we suspect the situation may change in the near future as a result of the growing human population and new roads. In the areas we have visited in W Harerghe, north of E Arsi, there is a considerable amount of deterioration from human activity (cutting of trees), cattle grazing, soil erosion and encroachment of invasive species. Solanum dennekense Damme (indigenous to Ethiopia and Somalia) and Calotropsis procera (W.T.Aiton)Dryand.(wide- spread in dry tropical Asia as well) are two woody species that are aggressively replacing other woody plants, in particular where the vegetation is overgrazed. We suspect this will be the situation elsewhere within the predicted range of Kalanchoe hypseloleuce and may be so also in E Arsi in the future. Climate change may constitute a risk given that the species relies on rain fall to initiate sprouting from seeds in the seed bank. Kalanchoe hypseloleuce doesn't fully meet the conditions to be evaluated as threatened under B1 since it only meets one of the three sub-criteria (B1biii — inferred decline in the quality of the habitat) but could be Vulnerable to Near Threatened (VU-NT) (IUCN 2016: 20). We don't think the habitat is severely fragmented or that the species occurs in fewer than 11 locations. However, we are uncertain about potential extreme fluctuations in the number of mature individuals. If the species is monocarpic, the populations alternate between mature individuals and individuals surviving as seeds in the seed bank. We have not observed successive maxima and minima in the number of mature individuals but it is possible that the number of mature individuals fluctuates a lot with the rather erratic rainfall in the region. Given the threat from habitat degradation is not imminent, we recommend the species to be listed as NT under B1biii (suspected decline in the quality of the habitat in the future), pending further research.
- Note on colouring of cell contents: A number of epidermal cells of the sepals, particularly on the abaxial side, have strikingly dark cell contents, turning almost black when the sepals wither. When injured during dissection with scalpel or needle, the contents of most cells of the sepals turn black. The 7 - 9 pm long glandular hairs on the corolla lobes and upper part of tube have darkened, but not black cell contents, particularly in the apical, glandular part. These dark cell contents prevented us from observing if the hairs are divided by cell walls.
- Africa: Ethiopia, Oromia Regional State.
- Acacia-Commiphora woodland and bushland on fine-grained red soil derived from Jurassic limestone and with floristic elements of the Transitional semi-evergreen bushland at higher elevation (see introduction); alt. 1350 - c. 1400 m.
- Morphology General Habit
- Erect succulent herb with single stems, to c. 3 m high, unbranched below inflorescence (basal parts not collected); all parts except corolla glabrous.
- Morphology Leaves
- Leaves uniformly distributed along stem, sessile, opposite decussate, spreading, slightly reflexed with upturned tip; lamina uniformly dull pale green, narrowly lanceolate to elliptic, to 28.5 x 3 cm, slightly smaller towards base, gradually smaller towards inflorescence, with shallowly upturned sides so as to be uniformly curved (U- shaped) in cross section, base cuneate, not amplexicaul, but connected by ± distinct interpetiolar lines, margins entire, apex acute, no venation apparent
- Morphology Reproductive morphology Flowers Androecium Stamens
- Stamens included, in 2 whorls of 4, upper whorl with filaments 0.5 - 1 mm long, lower whorl with subsessile anthers, whorls inserted 1 mm and 3 mm below apex of tube; anthers 0.8 - 0.9 x 0.5 - 0.6 mm, narrowing towards the tip.
- Morphology Reproductive morphology Flowers Calyx
- Sepals 4, free, spreading, narrowly triangular-lanceolate, 6 - 6.5 x 1.5 - 1.8 mm, apex acute, no venation apparent
- Morphology Reproductive morphology Flowers Corolla
- Corolla pure white, abaxially minutely glandular-papillate towards apex of tube and especially on the half of the lobes not covered by other lobes in bud; tube narrowly urceolate, 30 - 39 mm long, to c. 9 mm wide near base, c. 3 mm wide near apex, slightly keeled between sepals, base widening in late anthesis; lobes lanceolate, 8 - 10 x3- 4 mm, apex narrowly acuminate.
- Morphology Reproductive morphology Flowers Gynoecium Carpels
- Carpels 4, c. 12 mm long, with styles c. 9.5 mm long, stigma inconspicuous; each carpel with linear nectary at base, to 6 mm long, c. 0.3 mm wide; also with bluntly triangular gland-like structures, possibly nectaries, 0.7 mm long and wide, alternating with carpels.
- Morphology Reproductive morphology Inflorescences
- Inflorescence terminal, broadly ovoid, to almost 1 m long with 5 or 6 pairs of pedunculate cymes; cymes with peduncle to 20 cm, upper internodes 4 or 5, progressively shorter, most flowers clustered apically in 3- or 4- branched dichasia; bracts leaf-like, to 10 x 0.6 cm, somewhat recurved, uppermost bracts almost linear, c. 5 mm long; pedicel to 12 mm long
- Morphology Reproductive morphology Seeds
- Seeds c. 20 per carpel (follicle); only immature follicles and seeds seen.
- Morphology Stem
- Stem 20 - 25 mm in diam., cylindrical, smooth, dull pale green; internodes much shorter than leaves
Our new epithet, hypseloleuce, is a compound of two Greek adjectives. The first, ψηλός, ή, όν, ‘high, lofty, (metaphorically) stately',referstothe impressive height of the plant, it being one of the tallest known species of Kalanchoe in Africa. The second, λευκός, -ή, -όν, ‘light, bright, (of colour) white’, refers to the pure white flowers. The connecting vowel -o- is in agreement with Rec. 60G(a2) of the Code (McNeill et al. 2012). The generic name, Kalanchoe Adans. (Adanson 1763: 248), is said to be an adaptation of a Chinese name for a species in the genus (Harvey 1862) or derived from a Hindi word ‘kalanka’, meaning ‘rust’ or ‘ spot’ (Quattrocchi 2000). In botanical literature, Kalanchoe is treated as feminine and, in agreement with Art, 23.5 of the Code, the feminine form of the terminal adjective is used.
The species is distinguished from all other African members of the genus by the combination of the tall erect habit, to 3 m, glabrous except for the minutely glandular-papillate corolla lobes, the sessile, entire leaves, and pure white corollas with the tube 3 - 4 cm long. Kalanchoe prittwitzii is the species most likely to be confused with K. hypseloleuce, because ofits glabrous stems and leaves, fairly large stature and only slightly smaller flowers. However, it is very easily separated by the petiolate, broader, crenate to dentate margined leaves, as opposed to the sessile, narrower, entire margined leaves of K. hypseloleuce. It also differs by the smaller, entirely glabrous, mainly yellow, corolla with the tube 13 - 28 mm long, as opposed to the larger, partly papillate, pure white, corolla, tube 30 - 39 mm long, of K. hypseloleuce. Other African species of comparable habit (e.g. K. lanceolata (Forssk.) Pers.) have crenate to dentate margined leaves and smaller, yellow, orange or red corollas less than 3 cm long. Other species with similarly long, white, corollas (e.g. K. schimperiana A. Rich.) are perennials with stems decumbent at the base and with petiolate leaves with crenate to dentate margins.
Relationships amongst the mainland African species of Kalanchoe have never been investigated in any detail. Gehrig et al. (2001) presented a molecular phylogeny of the genus as a whole but this concentrated primarily on the many Madagascan members of the genus and included only a small selection of the mainland species. The analysis showed that these formed a monophyletic group apparently derived from within one of the three main Madagascan groups recognised but it lacked any useful resolution within this group. It does however show that we should look for relationships of the new species from amongst the species found on mainland Africa. The oldest collection of the new species, Burger 3596, was originally cited as the only record of Kalanchoe prittwitzii for the Flora of Ethiopia and Eritrea (Gilbert 1989). This was based on the robust stem, apparent lack of any indumentum and the length of the corolla. The material was too incomplete to show the habit and leaf shape and the distinctive minute glandular papillae on the corolla were missed.
The much more complete second collection has shown that that determination was mistaken but it should be noted that K. prittwitzii must be retained in the Ethiopian Flora as there has been a subsequent genuine collection of this species from within the Flora area, Friis et al. 8738 from 20 km NW of Moyale. The diagnostic features of Kalanchoe hypseloleuce are the tall, solitary stems, the total lack of indumentum except for the corolla, the distinctive sessile, narrow, entire leaves and the pure white flowers with distinctive minutely glandular-papillate lobes. The small and scattered clumps of tall and stiffly erect stems look extremely similar in habit and distribution of individuals in small, clustered populations to those of known monocarpic species such as K. densiflora Rolfe and K. lanceolata. From our field studies of characteristic populations in E Arsi and from comparisons with other African species of Kalanchoe of known life span we believe K. hypseloleuce to be monocarpic and to grow opportunistically from seeds in the soil seed bank.
The indumentum of the corolla needs good magnification to see but provides a good diagnostic character. In K. hypseloleuce, the indumentum is of densely packed, minute, blunt papillae distributed primarily on the outside of the corolla lobes and only spreading a short way along the corolla tube, which is mostly glabrous. The only species seen with an essentially similar corolla indumentum is K. usambarensis Engl. & Raym.-Hamet, which also has minutely papillate corolla lobes and glabrous corolla tube but the two species differ in virtually all other characters, as K. usambarensis is a small, clump-forming perennial with petiolate leaves and small, red corollas. The vast majority of the East African species have entirely glabrous corollas. Two species, K. schimperiana and K. citrina Schweinf. have densely pubescent, almost tomentose, corolla tubes with the corolla lobes more sparsely hairy, quite different from our new species in both the type of hairs and the pattern of their distribution. Hairy corollas also occur in K. densiflora and K. lanceolata but these are uniformly very sparsely glandular hairy and again quite different. There is a good correlation amongst the African species between corolla length and colour, with all white-flowered species having corolla tubes more than 30 mm long, probably hawk-moth pollinated, whilst all the yellow, orange, pink and red flowered species have corolla tubes up to 28 mm long.
The other white- flowered species, Kalanchoe aubrevillei Cufod., K. marmorata Baker, K. peteri Werderm., K. quartiniana A. Rich. and K. schimperiana, are all clump-forming perennials with distinctly petiolate, crenate or dentate leaves and do not seem to be closely related. Other apparently monocarpic species most similar in habit, such as Kalanchoe densiflora, K. lanceolata, K. mitejea Leblanc & Raym.-Hamet and K. nyikae Engl., all differ by the smaller yellow corollas, tubes to 22 mm long which are entirely glabrous or uniformly very sparsely glandular hairy. K. mitejea and K. nyikae approach K. hypseloleuce in overall size and in having entire leaves but the leaves of both species are much broader and are very distinctly petiolate. Other species with entire leaves are all clump forming perennials much smaller in stature.
- The two known gatherings both flowered in November to December, which is during the autumn rainy season.
- Type: Ethiopia, Oromia, Arsi, at road Mechara - Sheik Hussein, 9 km from Scianan Gorge towards Elele R., 1375 m a.s.l., 13 Nov. 2015, I. Friis, Wege Abebe & Ermias Getachew 15694 (holotype ETH!; isotypes C[C10021858]!, K[K001129396]!).
- None recorded.
First published in Kew Bull. 72(2)-30: 6 (2017)
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The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0