Desertia, Martínez-Azorín & Pinter & Wetschnig, 2015
|
publication ID |
https://doi.org/ 10.11646/phytotaxa.221.3.1 |
|
persistent identifier |
https://treatment.plazi.org/id/502A8792-2322-FFC9-F19A-ED16FDD6FDF3 |
|
treatment provided by |
Felipe |
|
scientific name |
Desertia |
| status |
|
Taxonomy of Desertia View in CoL , Whiteheadia and Namophila
1. Desertia Mart. -Azorín, M.Pinter & Wetschnig gen. nov. ( Figs. 1 − 4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 7 − 10 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ; fig. 8 in Müller-Doblies & Müller-Doblies 1997: 81).
Desertia differs from Whiteheadia ( W. bifolia ) and Massonia by the papillose bracts and subcampanulate flowers with straight, suberect or slightly spreading free portion of tepals and the sinuous-rugose seeds ( Table 1). Whiteheadia differs from Desertia by the larger, leafy, glabrous bracts, which are patent at early stages of inflorescence development; the subrotate flowers with patent free portions of tepals with regards to the perigone tube, which curve upwards in the upper portions; the larger anthers before dehiscence; the hooked style; and the smooth seeds ( Table 1). Massonia differs from Desertia by the subcapitate, sessile, raceme, not distinctly elongated above ground level; the bracts lacking distinct papillae; the absence of a distinct apical coma of sterile bracts; the free portion of tepals being patent to strongly reflexed with regards to the perigone-filaments tube, at least at the base; and the smooth seeds ( Table 1).
Type (holotype):— Desertia etesionamibensis ( U.Müll.-Doblies & D.Müll.-Doblies) Mart.-Azorín, M.Pinter & Wetschnig
Decidous geophyte. Bulb solitary, hypogeal, ovate-globose. Leaves two, synanthous, opposite, appressed to the ground, green with undefined, longitudinal, darker green stripes. Inflorescence, spiciform-racemose, multiflowered, distinctly elongated above ground level, surmounted by a coma of small, sterile floral bracts. Bracts lanceolate, membranous, strongly papillose on both sides and margin, erect to connivent at early stages of inflorescence development.Flowers subcampanulate, white or yellowish-green, patent to suberect, shortly pedicellate, honey-scented; tepals glabrous and entire or slightly papillose and denticulate on margins, straight, suberect or slightly spreading, fused below to form a short tube; filaments adnate to perigone and arising above the perigone tube, uniseriate, shortly connate above perigone; anthers yellow with pink-violet flush, dorsifixed. Ovary green, ovate to obovate-oblong; style mostly white, narrow, erect or slightly arcuate; stigma minute. Capsule widely ovate to obovate in lateral view, trigonous and deeply winged in apical view. Seeds more or less globose, apiculate, with a distinct hilum and a slightly prominent raphe, with sinuous rugosity.
Etymology:— Desertia (desertum lat. = desert); referring to desert habitats where the representatives of the new genus occur.
Biogeography and ecology:—Endemic to south western Namibia and north western South Africa. It occurs from farm Weissenborn and Dikwillem in Namibia to Richtersveld in South Africa, found among rocks and boulders on rocky hillslopes.
1a. Desertia etesionamibensis (U.Müll.-Doblies & D.Müll.-Doblies) Mart.-Azorín, M.Pinter & Wetschnig comb. nov.
Bas.: Whiteheadia etesionamibensis Müller-Doblies & Müller-Doblies (1997: 82) ( Figs. 1 − 4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 5a View FIGURE 5 ; figs. 8a, 8b, 8e, 8f, 8g 1, 8i1, 8h, 8j in Müller-Doblies & Müller-Doblies 1997: 81).
Type:— NAMIBIA. Witputz (2716): Aurus Mts., E of summit (Diamond area nº1) (- CB), S-facing slope, ca. 800 m of elevation, 18 September 1988, Müller-Doblies 88144n (holotype, WIND; isotypes, B, BTU, G, K, LI, M, MO, NBG, PRE, S, Z; not seen, apparently not yet deposited in any of the cited herbaria, including the holotype) .
Deciduous geophyte. Bulb 2 − 3 × 1 − 2 cm, solitary, hypogeal, ovate-globose. Leaves 5 − 10 × 1.5 − 6 cm, two, synanthous, opposite, appressed to the ground, ovate, with entire to minutely denticulate margin, green, with undefined, longitudinal, darker stripes. Inflorescence 3 − 7 cm long, solitary, spiciform-racemose, distinctly elongated above ground level, with 10 − 30 flowers, surmounted by a coma of small, inconspicuous, sterile, floral bracts. Bracts 10 − 15 × 4 − 6 mm, lanceolate, membranous, papillose on both sides and margin, the uppermost ca. 7 × 3 mm, white with a central longitudinal green band on the upper half, mostly hidden by flowers. Flowers subcampanulate, patent to suberect, pure white with a green longitudinal central band in the upper portion of tepals, honey-scented; tepals 10 − 16 × 3 − 4 mm, lanceolate, acute, glabrous, entire, straight, suberect or slightly spreading, fused below to form a short tube 3 − 4 mm long; filaments adnate to perigone and arising above the perigone-filaments tube, uniseriate, free portions 4 − 6 mm long, lanceolate, shortly connate above perigone for ca. 1 mm; anthers before dehiscence ca. 2 mm long, ca. 1 mm long after dehiscence. Ovary 4 − 5.5 × 3.5 − 4.5 mm, green, obovate-oblong; style 4 − 7 mm long, 0.6 − 1 mm wide at the base; mostly white, greenish in the lower third, narrow, erect or slightly arcuate, stigma minute. Capsule 7 − 11 × 7 − 13 mm, widely obovate in lateral view, deeply three lobed or winged in apical view. Seeds 2 − 2.3 × 1.5 − 1.8 mm, more or less globose, apiculate, with a distinct hilum and a slightly prominent raphe, glossy black, with distinct sinuous rugosity.
Comments on the type collection:—We were not able to study the type material of D. etesionamibensis , since it has not yet been deposited in any of the herbaria cited by Müller-Doblies & Müller-Doblies (1997), including the holotype at WIND (E. Strauss pers. comm.). However, figure 8 in Müller-Doblies & Müller-Doblies (1997: 81) includes detailed drawings of bracts, flowers and capsules from the type collection in comparison with a collection from the Rooiberg. Provided that Whiteheadia etesionamibensis was described as having white flowers, and that the illustration of the gynoecium from the type collection by Müller-Doblies & Müller-Doblies (1997) shows widely obovate and truncate ovary that extends into a shorter style with regards to the collection form the Rooiberg , point out that Desertia etesionamibensis , as originally described, represents the white-flowered species with broader, truncate ovaries and shorter styles among other characters, as accepted in the present study.
Etymology:—The specific epithet means growing in winter-rainfall region characterised by ethesial winds, referring to etesiai winds that (in ancient Greece) used to bring winter rainfall; the term ‚ethesial regions’ is still used by climatologists to designate regions experiencing mediterranean-type climate ( Müller-Doblies & Müller-Doblies 1997).
Biology:— Desertia etesionamibensis flowers in the wild from May to July, and fruits arise from June to August. In cultivation in the Northern Hemisphere (Graz, Austria) this species flowers from late October to January, and capsules are well developed from February to April.
Distribution:— Desertia etesionamibensis is known to us from four localities in south western Namibia, farm Weissenborn and Dikwillem in the Lüderitz district, the Aurus Mountains (the type locality) and the Hunsberge ( Fig. 6 View FIGURE 6 ).
Habitat:—Among rocks and boulders on rocky hillslopes.
Diagnostic characters:— Desertia etesionamibensis is characterized by the white flowers; the glabrous tepals with entire margin; the obovate and truncate ovary, 3.5 − 4.5 mm wide; the style 5 − 7 mm long; the capsules 7 − 11 × 7 − 13 mm; and the seeds glossy black, with a slightly prominent raphe and distinct sinuous rugosity.
Additional material studied:— NAMIBIA. Aus (2616): SWA, Lüderitz district, farm Weissenborn, ravine near farmhouse (- AB), between rocks, 4 July 1949 [in flower and fruit], H. Kinges 2387 ( M0274451 !, PRE0049670 About PRE !) ; Aus (2616): Dikwillem , ca. 20 km NW of Aus (- AC), rock crevices, ca. 900–1150 m elevation, ex hort. in Graz, Austria on 15 December 2014 [in flower], corresponding to Müller-Doblies 88042 C ( GZU!) ; Chamaites (2717): Nuobrivier (- CA), unweit Apollogrotte , Hunsberge, am Berghang im Gestein, 9 June 1976 [in fruit], W. Giess & M. Müller 14305 ( M, WAG1158220 About WAG !, WIND000003262 About WIND photo!) .
1b. Desertia luteovirens Mart. -Azorín, M.Pinter & Wetschnig sp. nov. ( Figs. 5b View FIGURE 5 , 7 − 10 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 ; fig. 8d, 8g, 8g 2, 8g 3, 8i2, 8k in Müller-Doblies & Müller-Doblies 1997: 81).
Desertia luteovirens is in some extent similar to its relative D. etesionamibensis , but it differs by the pale yellow-greenish flowers; the tepals slightly papillose with denticulate margins; the ovary ovate, tapering to the style, 2.5 − 3.2 mm wide; the style 3.5 − 4 mm long; the capsule 12 − 21 × 13 − 25 mm; and the seeds dull black, with an indistinct raphe and finely sinuous rugosity.
Type:— NAMIBIA. Witputz (2716): ca. 15.5 km NW of Rosh Pinah (- DC), ca. 756 m of elevation, 19 February 2015 ex hort. in Austria, Steiermark, Graz, Botanical Garden of the Institute of Plant Sciences of the University of Graz, C. Craib s.n. (holotype, WIND! isotypes, ABH!, GZU!).
Deciduous geophyte. Bulb 2 − 4 × 1.5 − 3 cm, solitary, hypogeal, ovate-globose. Leaves 6 − 15 × 4 − 10 cm, two, synanthous, opposite, appressed to the ground, ovate, entire with minutely denticulate margin, green, with undefined, longitudinal, darker stripes. Inflorescence 7 − 11 cm long, solitary, spiciform-racemose, distinctly elongated above ground level, with 10 − 80 flowers, surmounted by a coma of small, sterile, linear-lanceolate floral bracts. Bracts 6 − 22 × 4 − 6 mm, lanceolate, membranous, densely papillose on both sides and margin, the uppermost ca. 7 × 2 − 3 mm, greenish with a central longitudinal darker green band, mostly hidden by flowers. Flowers subcampanulate, patent to suberect, greenish-yellow with green longitudinal bands in the upper portion of tepals, patent to suberect, honey-scented; tepals 10 − 16 × 3 − 4 mm, lanceolate, acute, slightly papillose with denticulate margins, straight, suberect or slightly spreading, fused below to form a tube 3 − 4 mm long; filaments adnate to perigone and arising above the perigone-filaments tube, uniseriate, free portions 4 − 6 mm long, lanceolate, shortly connate above perigone for ca. 1 mm; anthers before dehiscence ca. 2 mm long, ca. 1 mm after release of pollen. Ovary 4.5 − 5.5 × 2.5 − 3.2 mm, green, ovate, tapering to the style; style 3.5 − 4 mm long, 0.5 − 0.7 mm wide at base, mostly white, greenish in the lower third, narrow, erect; stigma minute. Capsule 12 − 21 × 13 − 25 mm, widely subovate to obovate in lateral view, trigonous and deeply winged in apical view. Seeds 1.9 − 2.1 × 1.8 − 1.9 mm, more or less globose, apiculate, with a distinct hilum and an indistinct raphe, dull black, with finely sinuous rugosity.
Etymology:—The specific epithet comes from “luteo” = yellow and “virens” = green; referring to yellow-green colour of the flowers.
Biology:— Desertia luteovirens flowers in the wild around January on the farm Spitskop in Namibia and in July in Richtersveld in South Africa. In cultivation in the Northern Hemisphere (Graz, Austria), D. luteovirens flowers from late January to April and capsules are well developed from March to May. It was observed that different plants from the type locality flowered at different times in successive years, and that flowering and fruiting plants occurred together. This may point out that the species is adapted to flower in response to suitable environmental conditions, adapting the anthesis to the rainfall periods. Under equal conditions of cultivation in Graz, Austria, D. luteovirens flowers later than D. etesionamibensis .
Distribution:—The new species is known to us from several localities in south western Namibia, and north western South Africa. In Namibia it occurs in the Aurus Mountains, and the surroundings of the farm Spitskop, Rosh Pinah and Lorelei, whereas in South Africa it is only known from east of Sendelingsdrif in the Richtersveld National Park, the latter locality being the first record of Desertia in South Africa (cf. Manning & Goldblatt 2013) ( Fig. 6 View FIGURE 6 ).
Habitat:—Among rocks and boulders on rocky hillslopes.
Phylogenetic relationships:—Our phylogenetic studies on Desertia and related genera (not shown) evidence important differences between the two species of Desertia . Two samples of Desertia luteovirens showed a deletion of 94 base pairs in the trn L-F plastidial region, which is absent in Desertia etesionamibensis , this therefore adding further arguments for its recognition as a distinct species in the genus.
Additional specimens and material studied:— NAMIBIA. Witputz (2716): Northern ridge of Aurus Mountains (- CB), mountain slope, stony/rocky soil, 683 m elevation, 11 August 2001 [in flower] C. A. Mannheimer 1592 ( WIND 77745.0 photo!; Mannheimer 2002: 68 photo!) ; Witputz (2716): Sperrgebiet, Aurus Mountains , lower peaks to SE of low neck SE of main beacon (- CB), granite kloof and slopes facing SW, 7 September 1992 [in flower] E. G. H. Oliver 10179 ( WIND000059136 About WIND photo!) ; Witputz (2716): Distrikt Lüderitz— Süd, Numais-Bänke , Farm Spitskop (- DC), 1 January 1963 [in flower], H. Merxmüller & W. Giess 3408 ( M0274455 !) ; Witputz (2716): Lüderitz-Süd Distr., Rosh Pinah (- DD), mountain slopes above the mine, NE of the village, and flats below, rocks, 2 July 1947 [in bud], B. Nordenstam & J. Lundgren 491 ( S09-7574 !) ; Witputz (2716): Rosh Pinah, Farm Namuskluft , high mountain North of road, +- 5 km from house (- DD), shady, wet gorge, steep slope, in the cracks of a dark grey boulder, 589 m elevation, 10 September 2002, S. Bartsch & S. Loots SB1092 ( WIND 83150.0 photo!, Mannheimer et al. 2008: 29 photo!) ; Oranjemund (2816): N of Lorelei (- BB), growing on 35º slope with 0 aspect, 1 August 1989 [in flower and fruit], B. Strohbach 122 ( WIND000056841 About WIND photo!) . SOUTH AFRICA. Northern Cape. Oranjemund (2816): Near Swartpoort, Noorskoppe (referring to Euphorbia hottentota ), Richtersveld National Park , high peaks just N of road (9 km from Sendelingsdrif on road to Oena) (- BB), succulent karroo, stony soil/rocky, 28 July 1993 [in flower], E. J. Van Jaarsveld 13247 ( PRE 763394.0!) .
Other specimens of Desertia cited in Müller-Doblies & Müller-Doblies (1997) but not available:— NAMIBIA. Aus (2616): Dikwillem, ca. 20 km NW of Aus (- AC), rock crevices, ca. 900–1150 m elevation, 27 July 1988, Müller-Doblies 88042 C ( B, BTU, K, LI, PRE, WIND) ; Witputz (2716): Rooiberg , top and upper S slope (Diamond area nº1) (- CB), stony ground and crevices, ca. 1050 m elevation, 16 September 1988, Müller-Doblies 88141k ( BTU, WIND) ; Witputz (2716): Numaeis , südl. Witputz, (- DC), September 1957, Rusch f. 4688 ( M, on loan to U. & D. Müller-Doblies) ; Witputz (2716): Spitskop , valley with waterfall, 6 km from Rosh Pinah road, kloof around the seasonal waterfall (- DC), ca. 700 m elevation, 6 August 1988 in bud, Müller-Doblies 88064b ( BTU) ; Witputz (2716): farm Spitskop, valley entry 1, 2 km S of farm house (- DC), rocky S facing slope, ca. 650 m elevation, 27 September 1989 nearly flowering, Müller-Doblies 89123g ( B, BTU, NBG, WIND, S, Z) ; Witputz (2716): Namuskloof, 7 km N of farm house (- DD), S facing slope with quartzite, ca. 450 m elevation, 6 August 1988, Müller-Doblies 88062e ( BTU, WIND) ; Oranjemund (2816): Diamond area nº1, Obib Mountain Peak, (- BA), rocky S facing slope, 3 September 1989, A. E. Van Wyk 9005 ( PRE, PRU, WIND) .
| U |
Nationaal Herbarium Nederland |
| M |
Botanische Staatssammlung München |
| E |
Royal Botanic Garden Edinburgh |
| CB |
The CB Rhizobium Collection |
| WIND |
National Botanical Research Institute |
| B |
Botanischer Garten und Botanisches Museum Berlin-Dahlem, Zentraleinrichtung der Freien Universitaet |
| BTU |
Technische Universität Berlin |
| G |
Conservatoire et Jardin botaniques de la Ville de Genève |
| K |
Royal Botanic Gardens |
| LI |
Biology Centre of the Upper Austrian State Museum - Herbarium |
| MO |
Missouri Botanical Garden |
| NBG |
South African National Biodiversity Institute |
| PRE |
South African National Biodiversity Institute (SANBI) |
| S |
Department of Botany, Swedish Museum of Natural History |
| Z |
Universität Zürich |
| SWA |
Swansea Museum |
| H |
University of Helsinki |
| AC |
Amherst College, Beneski Museum of Natural History |
| C |
University of Copenhagen |
| GZU |
Karl-Franzens-Universität Graz |
| CA |
Chicago Academy of Sciences |
| W |
Naturhistorisches Museum Wien |
| ABH |
Universidad de Alicante |
| A |
Harvard University - Arnold Arboretum |
| DD |
Forest Research Institute, Indian Council of Forestry Research and Education |
| NE |
University of New England |
| J |
University of the Witwatersrand |
| N |
Nanjing University |
| BB |
Buffalo Bill Museum |
| BA |
Museo Argentino de Ciencias Naturales Bernardino Rivadavia |
| PRU |
University of Pretoria |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.