Introduction

While preparing an account of Asparagaceae for Flora Zambesiaca (FZ), the following four new species were found undescribed and described. With the account of Asparagaceae completed for much of tropical and South Africa (Jessop 1966 for Southern Africa; Obermeyer & Immelman 1992 for South Africa; Sebsebe Demissew 1995 for the Flora of Somalia, 1996 for the Flora of Ethiopia and Eritrea and 2006 for the Flora of Tropical East Africa), the identification of the new taxa is relatively simple. In the FZ area, 35 species are known to occur; of these, four are described here as new: A. botswanicus Sebsebe A. chimanimanensis Sebsebe, A. radiatus Sebsebe and A. richardsiae Sebsebe.

Specimens of Asparagus from BM, BR, E, EA, LISC, K, PRE and SRGH have been consulted for the revision of Asparagaceae in the FZ area.

The genus Asparagus has been divided into two subgenera: subgenus Asparagus and subgenus Myrsiphyllum (Malcomber & Sebsebe 1993) and the four new species belong to subgenus Asparagus. The African species in this subgenus can be easily divided in two groups based on whether the flowers are solitary or occur in fascicles (including A. africanus and related species) or the flowers being on raceme inflorescences (including A. falcatus and related species). Two of the new species, A. botswanicus and A. richardsiae, have flowers that are solitary, while A. chimanimanensis and A. radiatus have flowers in racemose inflorescences.

Asparagus botswanicus Sebsebe sp. nov. A. africanae Lam. similis sed caule brevi (25 – 60 cm (nec 50 cm – 4 m) longo), habitu erecto (nec scandenti), ramulis et cladodiis angulatis papillas ferentibus (nec rotundatis papillis carentibus), floribus solitariis (nec 2 – 10 fasciculatis), pedicellis supra (nec infra) medium articulatis differt. Typus: Botswana, Northern Division, 69 km W of Nokaneng, fr. 12 March 1965, H. Wild & R. B. Drummond 6895 (holotypus K; isotypi LISC, ?SRGH).

Erect shrub 25 – 60 cm high from an erect rhizome. Stems branching from base. Branches in older parts terete, in younger parts angular, lined with raised papillae, with or without very short spines 0.5 – 1 mm long. Cladodes in fascicles of 3 – 6, angular with raised papillae, unequal, 4 – 10 mm long; stipules white, elliptic with acuminate apex, overlapping, 1 – 1.5 × c. 0.5 mm. Flowers solitary, axillary in cladode fascicles; pedicels 2.5 – 3.5 mm long with raised papillae, articulated above the middle. Perianth of 6 tepals, c. 2.5 × 0.6 mm. Stamens 6, with filament c. 2 mm long. Berry orange at maturity, c. 6 mm in diam., 1-seeded. Fig. 1.

Fig. 1
figure 1

Asparagus botswanicus. A habit; B details of cladodes; C flower side view; D tepal; E fruit side view showing the pedicel articulated above the middle. A, C – E from Wild & Drummond 6895 (K); B from Wild & Drummond 6895 (LISC). Drawn by Juliet Williamson.

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Distribution. Known so far from a single locality in the Northern division of Botswana.

Habitat. Burkea africana-Combretum zeyheri savanna with Terminalia sericea, Ochna pulchra, Bauhinia micrantha and Dichrostachys cinerea on deep, fine-grained sand; no altitude given.

Collection examined. Botswana. N: 69 km W of Nokaneng, fr. 12 March 1965, H. Wild & R. B. Drummond 6895 (holotype K; isotypes LISC, ?SRGH).

Conservation Status. Data Deficient. The species is known only from the type collection made in 1965. This might be due to poor collecting in the area or the rarity of the species. Therefore it is very difficult to assess its conservation status based on the Criteria set by IUCN (2001).

Etymology. Asparagus botswanicus “the asparagus of Botswana” is named after the country Botswana, where the species is apparently endemic.

Notes. The new species is related to the widespread Asparagus africanus Lam. but differs in its small size (stems 25 – 60 cm long), erect habit, angular branches, and cladodes with raised papillae, and solitary axillary flowers with pedicels articulated above the middle. In contrast, A. africanus has stems up to 4 m long, an erect to scandent habit, branches and cladodes terete without papillae, axillary and/or terminal flowers and pedicels articulated below the middle.

Asparagus richardsiae Sebsebe sp. nov. A. psiluro Welw. ex Baker similis sed cladodiis ad anthesin praesentibus (nec absentibus), pedicellis supra medium articulatis et infra articulationem pubescentibus (nec infra medium articulatis nec omnino glabris) differt. Typus: Zambia, Mbala (Abercorn) Distr., Chilongowelo, c. 1470 m, fl. 24 Dec. 1951, H. M. Richards 127 (holotypus K).

Stiff upright shrub to 2 m high. Branches pubescent with white erect hairs to glabrous, with spines on main stems c. 2 mm long, curved downwards. Cladodes fasciculate, 4 – 10 together, subulate, erect or bent, 5 – 10 mm long. Flowers axillary, solitary in the axils of cladodes; pedicels 4 – 5 mm long, articulated above the middle, the lower part pubescent and the upper part glabrous to rarely puberulous. Perianth greenish-yellow (fide Richards 127) tinged brown, 2.5 – 3 mm long; bracts ovate c. 1 × 1 mm; ovary ovoid, c. 1 mm long; style c. 1 mm long with branching stigma. Fruit not seen. Fig. 2.

Fig. 2
figure 2

Asparagus richardsiae. A habit; B root stock; C part of root stock in section; D detail of branch with spine; E flower & cladode fascicles; F flowering branch with cladode and flower showing the pedicel articulated above the middle; G flower side view, one tepal removed to show stamens and style. A, D – E from Mrs Richards 127; B – G from Natural History Club 67. Drawn by Juliet Williamson.

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Distribution. Known so far only from Mbala (Abercorn) Distr., in Chilongowelo and near junction Kariba power line & Leopards Hill Road.

Habitat. Thick bush near streams and hill sides on gentle slopes in shade of trees and bushes; 1200 – 1500 m.

Collections examined. Zambia. N: Mbala (Abercorn) Distr., Chilongowelo, c. 1470 m, fl. 24 Dec. 1951, Richards 127 (holotype K); near Kariba Power Line and Leopards Hill road, c. 1200 m, sterile, 24 Nov. 1951, Lusaka Natural History Club 67 (K).

Conservation. Data Deficient. Known only from two collections; more collections and field observations are required.

Etymology. Asparagus richardsiae is named in honour of Mrs H. M. Richards, who devoted much of her life to collecting plants in south-central Africa and collected the type specimen of this species.

Notes. Asparagus richardsiae resembles A. psilurus. It differs in the presence of cladodes at anthesis and pedicels articulated above the middle, glabrous above and hairy below the articulation. In contrast, in A. psilurus the cladodes are absent at anthesis, pedicels articulated below the middle and glabrous throughout.

Asparagus chimanimanensis Sebsebe sp. nov. A. rigidi Jessop caulis striatis et cladodiis brevibus stellatim dispositis similis sed inflorescentiis racemosis, 2 – 4.5 cm (nec 0.6 – 1 cm) longis, pedunculis longioribus 4 – 5 mm (nec c. 2 mm) longis, ramulis pyramidalibus (nec caudam vulpis simulantibus) differt. Typus: Zimbabwe, E, Melsetter Distr., Chimanimani Mts, Chikukwa’s Kraal, banks of river near falls, fr. 16 Nov. 1967, Mavi 653 (holotypus K; isotypi LISC, SRGH).

Erect shrub 40 – 50 cm high. Stem and branchlets with regular zigzag branching, branchlets ribbed, glabrous. Spines on main stems and below branchlets, 2 – 5 mm long, curved downwards. Spinules below flowers absent. Cladodes solitary or in fascicles of 2 – 4 together, stellately arranged on a zigzagging branchlet, 5 – 10 × 1 mm, attenuate at the base, acute at the apex. Inflorescence simple or compound racemes, 2 – 4.5 cm long; bracts ovate c. 1.5 mm long. Flowers solitary or in fascicles of 2 – 4; pedicel (below articulation, 2 – 3 mm long), pedicel size not clear (because the part above the articulation had fallen off). Tepals caducous and hence not seen. Berry 7 – 9 mm in diam. Fig. 3.

Fig. 3
figure 3

Asparagus chimanimanensis. A habit; B branches with cladodes and inflorescences; C cladode; D detail of branch showing the ridges and spines; E flower side view (reconstruction); F fruit side view with pedicel articulated above the middle; G fruit showing the basal part with remains of tepals. A from Pedro 2322 (LISC); B – G from Mavi 653 (K). Drawn by Juliet Williamson.

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Distribution. Known so far only from the Chimanimani Mts in Zimbabwe and an unspecified area in Manica or Sofala in Mozambique.

Habitat. Banks of river near falls, growing amongst rocks; c. 2100 m (in Zimbabwe).

Collections examined. Zimbabwe. E: Melsetter Distr., Chimanimani Mts, Chikukwa’s Kraal, banks of river near falls, fr. 16 Nov. 1967, Mavi 653 (holotype K; isotypes LISC, SRGH); Gazaland, Chimanimani Mts, 2100 m, sterile, 26 Sept. 1906, Swynnerton 1092 (BM). Mozambique. MS: Manica E Sofala, 1948 (no specific dates), only in inflorescence with fallen flowers, Pedro 2322 (LISC).

Conservation Status. Data Deficient. Known only from the Chimanimani Mts and an area (not specified in Manica E Sofala in Mozambique. There are only three collections of this unique Asparagus species. More collections and field observations are required.

Etymology. Asparagus chimanimanensis refers to “the asparagus of Chimanimani Mts”, named after the mountain, where the type specimen was collected.

Notes. Asparagus chimanimanensis resembles A. rigidus Jessop from South Africa (Mpumalanga) on account of the ribbed branches and stellately arranged cladodes. However, it has a long racemose inflorescence, 2 – 4.5 cm long, a peduncle 4 – 5 mm long, and branches conically in outline, resembling a Christmas tree. In contrast, A. rigidus has flowers on a short peduncle c. 2 mm long, the peduncle including the flower is less than 1 cm long, and branching is cylindrical-fusiform like a ‘fox-tail’ in outline.

Asparagus radiatus Sebsebe sp. nov. A. aethiopico L. similis sed ramulis et axe inflorescenti rotundatis (nec striatis neque angulatis); ramulis griseis vel cinereis (nec pallide viridibus), pedicellis c. 2.5 mm (nec c. 3.5 mm) longis, ramulis et cladodiis radiatim dispositi differt. Typus: Mozambique, M: Maputo (Lourenço Marques), Goba, 23 Nov. 1944, F. A. Mendonça 3081 (holotypus LISC).

Climbing shrub to 3 m high. Stems and branches grey, glabrous and terete. Tubers lateral, 20 – 38 × 10 – 24 mm. Cladodes radiating, 6 – 14 in a fascicle, flattened, 8 – 13 × c. 2 mm, obovate, narrowed at the base, acute at the apex; epidermis with clear reticulation. Inflorescences racemose, branching once or twice, 5 – 8 cm long. Flowers 2 – 4 at each node. Pedicels c. 2.5 mm long, articulated at the base. Tepals white, elliptic, c. 3 × 1 mm. Fruits 7 – 8 mm in diam. Fig. 4.

Fig. 4
figure 4

Asparagus radiatus. A habit; B cladode; C inflorescence with fruits; D flower side view with pedicel articulated below the middle; E tepal with stamen; F fruit showing the basal part with remains of tepals. A – B from Mendonça 3078 (LISC); C – F from Mendonça 3081 (LISC). Drawn by Juliet Williamson.

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Distribution. Known only from the Goba Distr. near Maputo in Mozambique and in Umbeluzi Gorge in Swaziland.

Habitat. Dry rocky slopes on rhyolite, in Androstachys johnsonii dry forest; c. 110 m.

Collections examined. Mozambique. M: Maputo (Lourenço Marques): Goba, fr., 23 Nov. 1944, F. A. Mendonça 3081 (holotype LISC); st., 23 Nov. 1944, F. A. Mendonça 3078 (LISC). Swaziland. Umbeluzi Gorge, c. 4 km W of Siweni Siding, fl. (fallen), 3 Dec. 2006, J. E. & S. M. Burrows (ETH, K).

Conservation Status. Data Deficient. This species is known from the well collected region near Maputo (but only the two collections are seen in herbaria) and a single collection from Umbeluzi Gorge in Swaziland made recently. There is a need to carry out collecting and field observations in the area around Goba in Mozambique and in Umbeluzi Gorge in Swaziland.

Etymology. Asparagus radiatus, “the asparagus with radially arranged parts” refers to the verticillate (radial arrangment) of the cladodes, which is unique amongst the related species.

Notes. Asparagus radiatus is related to A. aethiopicus, a South African species. It differs in that A. aethiopicus has branches and inflorescence parts angled/striate (not terete), pedicels 3.5 – 4 mm long (not c. 2.5 mm) and cladodes not radially arranged. It also resembles A. natalensis, which is widespread in Africa from South Africa to Ethiopia. However, as well as the radiating cladodes, the new species differs by the cladodes and inflorescences being on separate parts (not intermingled with each other as in A. natalensis).