Sansevieria bangalalana Mollel, M.Burkart, Sikawa & Yinger, 2025

Burkart, Michael, Kavula, Kened Alfred, Constantine, Immaculate Kileo, Mollel, Neduvoto Piniel, Piniely, Luciana Naftal, Sikawa, Robert Augustino & Yinger, Barry R., 2025, Sansevieria bangalalana sp. nov. (Asparagales, Asparagaceae), close to extinction in the wild, and five other narrowly endemic and threatened species of Sansevieria from Tanzania previously unknown to science, European Journal of Taxonomy 1026, pp. 65-106 : 69-74

Sansevieria bangalalana Mollel, M.Burkart, Sikawa & Yinger sp. nov.

urn:lsid:ipni.org:names:77370777-1

Figs 1–6

Diagnosis

Sansevieria bangalalana sp. nov. is the only species of Sansevieria known presently that has capitate inflorescences and long, straight, bifacial (ʻflatʼ) but strongly inrolled leaves ( Figs2, 3A). The colouration of the flowers includes reddish brown, yellowish and greenish parts, which is also unique in the whole genus ( Fig. 4B). The flower tubes are only 25 mm long, much shorter than in any other species of the subgenus Capitulatus , to which this species belongs according to its inflorescence type.

Etymology

Sansevieria bangalalana sp. nov. is named for Bangalala Ward, where this species was found.

Type material

TANZANIA • Kilimanjaro Region, Same District, foothills of the North Pare Mountains ; 896 m a.s.l.; 14 Dec. 2021; B. Yinger & R.A. Sikawa YS 1026; on a strip of flat gently sloping land between a gravel road and a seasonal stream, probably inundated during the heaviest rains in season, growing together with extensive populations of Sansevieria volkensii Gürke , S. fischeri (Baker ex Dyer) Marais and scattered small trees, in an extremely arid area with a short rainy season; holotype: NHT [ 000001159 ].

Living specimens ex typo cultivated at TSF and POTSD.

Description

Rhizomatous herb, stemless, vegetative height ca 1 m, 1–2 leaves per shoot, forming loose clumps ( Figs 2, 3B). Rhizome subterranean but close to soil surface (ca 0–10 cm), rhizome diameter ca 38 mm, inner cortex of mature rhizome†† light brown. Leaves upright, strongly folded longitudinally ( Fig. 3A), very stiff, straight, blue green, slightly mottled, linear outline, to 1 m long or slightly longer, 60 mm wide, leaf base 73 mm wide, 19 mm thick, leaf adaxial surface forming a rounded to pentagonal channel from base to tip 7 mm deep at mid-leaf, adaxial surface slightly rough with light-dark pattern in transverse bands, margin pale orange (orange white 159 grp A), 1 mm long awn tip; leaf abaxial (= outer) surface with very numerous stomata sunk into the surface, with short to medium-long, nodose, straight to wavy, largely unconnected transverse ribs between them ( Fig. 5). Inflorescence ( Figs 3B, 4) on fully leaved shoot, capitate, axis 185 mm long overall, peduncle 93 mm long, 13 mm in diameter, grayed yellow, bearing 6 dry bracts ca 23 mm long, flower-bearing axis 92 mm long, flower-head 87 mm in diameter excluding anthers and styles, very dense with 3–4 flowers per partial inflorescence, bracts of partial inflorescences 7–15 mm long, 2–5 mm wide, herbaceous, lanceolate, without extrafloral nectaries. Flowers on pedicels ca 6 mm long, yellow green, without articulation; corolla tube light reddish brown, tip of buds green, proximal parts of lobes yellowish outside, bright white inside; overall flower length 36 mm, tube 25 mm long, lobes 11 mm long, 2 mm wide, diameter of closed flower shortly before anthesis 3 mm at the base, 2 mm at the narrowest point, 3 mm in the upper part, lobes strongly curling back at full anthesis (more than 360°); filaments white, 18 mm long, filiform, anthers 2–3 mm long; style straight, white, 47 mm long excluding ovary including stigma, 22 mm exserted from tube mouth, stigma translucent, 1 mm wide; ovary yellowish green, ovoid. Fruits and seeds unknown. Youth form (young shoots from leaf cutting) different from adult plant, leaf transect openly u-shaped, colouration fresh green with transversally oriented, whitish patterning; cataphylls similarly green but largely unpatterned ( Fig. 3C).

Ecology and distribution

Sansevieria bangalalana sp. nov. was only found at the type location, on a strip of flat gently sloping land between a gravel road and a seasonal stream, probably inundated during the heaviest rains in season, growing in dry bushland with small trees and extensive colonies of Sansevieria volkensii Gürke and S. fischeri (Baker ex Dyer) Marais.

Taxonomic remarks

Sansevieria bangalalana sp. nov. is unique in the combination of several features. There is no other species of Sansevieria known presently that has capitate inflorescences and long, straight, bifacial (ʻflatʼ) but strongly inrolled leaves. The leaf surface is outstanding and the colouration of the flowers is also unique, although difficult to describe, including reddish brown, yellowish and greenish parts. Figure 4 gives an appropriate impression. Last, the flower tubes are only 25 mm long, which is extremely short for a capitate-flowered species.

From a distance, however, S. bangalalana sp. nov. is hard to distinguish from S. fischeri and large forms of S. volkensii which both are encountered regularly in the same region.

Tentative threat assessment

Critically endangered: CR B2ab(iii); C1+2(i); D.

Sansevieria bangalalana sp. nov. was first observed by us (RAS, BRY) on December 14, 2021, when a sterile living specimen was collected ( YS 1026). At that time, a strip of flat land between the Bangalala Road and the foothills of the North Pare Mountains was covered with extensive colonies of Sansevieria volkensii , S. fischeri , and colonies of another taxon, probably S. bangalalana . This site is about 100 m wide and 3 km long. Because of the variability of S. volkensii and S. fischeri , it was not clear whether or not we were seeing something new. Only when YS 1026 flowered at TSF in early March, 2022, it became clear that it is a unique new species.

On several visits to the site (October and November, 2023, and January, 2025) we found that almost the entire area possibly occupied by S. bangalalana sp. nov. had been cleared of all vegetation, its remnants burned, and the whole site scraped to bare soil. On October 27, 2023, we observed 22 leaves in a heavily stressed colony at roadside, mostly covered with soil ( Fig. 6), of which only four survived to January, 2025, so regarding the morphology of S. bangalalana there were fewer than 4 shoots remaining on few square meters in a very unfavourable situation. On this last visit, a second colony of about 25 plants including one inflorescence was found in another location. There is now very little natural vegetation remaining anywhere between the main highway and the town of Bangalala, as most of it has been converted to agricultural land. There is virtually no chance that any other plants of S. bangalalana will remain there.

In conclusion, S. bangalalana sp. nov. is imminently threatened by extinction in the wild. IUCN threat category CR (critically endangered) applies under criteria B2 (AOO < 10 km ²), C1 (less than 250 mature individuals and strong population decline), C2i (<50 mature individuals in both subpopulations), and D (<50 mature individuals overall). Additionally, we suppose that the probability of extinction in the wild within 10 years is> 50% (criterion E). Apart from the plants in cultivation at TSF, POTSD, and one other collection, only one small stand (ca 25 shoots) and the four leaves by the road and largely covered with piled soil are left. The present threat status according to our data is CR, close to EW.