Rhadamanthus Salisb., Gen. Pl.

Martínez-Azorín, Mario, Crespo, Manuel B., Alonso-Vargas, María Ángeles, Pinter, Michael, Crouch, Neil R., Dold, Anthony P., Mucina, Ladislav, Pfosser, Martin & Wetschnig, Wolfgang, 2023, A generic monograph of the Hyacinthaceae subfamily Urgineoideae, Phytotaxa 610 (1), pp. 1-143 : 67-72

15. Rhadamanthus Salisb., Gen. Pl. [Salisbury]: 37 (1866)

( Figs 36–38 ). Typus generis:— R. convallarioides (L.f.) Baker (holotype).

= Drimia sect. Rhadamanthus (Salisb.) J.C.Manning & Goldblatt in Strelitzia 40: 129 (2018). Typus sectionis:— R. convallarioides (L.f.) Baker (holotype).

= Drimia sect. Sclerophyllae J.C.Manning & Goldblatt in Strelitzia 40: 101 (2018). Typus sectionis:— D. sclerophylla J.C.Manning & Goldblatt ≡ Urginea rigidifolia Baker (holotype).

Description:—Bulbous geophyte. Bulb hypogeal, ovoid to globose, with compact white, scales, rarely loose and pink. Leaves 1‒20 per bulb, hysteranthous, 1.5‒30 cm long, filiform and subterete or ovate-lanceolate to suborbicular and flat or cucullate, leathery, green, sometimes purplish at base, smooth, glabrous or rarely ciliate, sometimes surrounded by transversally barred cataphylls at base. Inflorescence racemose, usually elongated, 2‒22 cm long, with 5‒50(–70) flowers; peduncle terete, erect, 5‒30 cm long, smooth or commonly scabrid-puberulous at base; pedicels subpatent, straight to arquing, 3‒20 mm long, glabrous or rarely minutely scabrid. Bracts narrowly lanceolate, 1‒2 mm long, lowermost with spur 0.5‒1.5 mm long; bracteoles absent. Flowers stellate, campanulate or urceolate, erect-patent to nodding, diurnal. Tepals 6, 3‒10 mm long, white, yellow, brown or pinkish, with darker longitudinal band, free and patent to reflexed or connate for up to 3 mm and then campanulate or urceolate. Stamens 6, connivent to style or spreading; filaments free and 2‒3 mm long or adnate to tepals for up to 2 mm from base and free portions 0.3‒1.5 mm long; anthers medifixed, dehiscing by apical slits to their whole length, oblong to sagittate, sometimes basally apendiculate. Ovary ovoid, trigonous, 1.5‒4.0 mm long, pale green to yellowish, well differentiated from style. Style erect, 0.5‒2.5 mm long. Stigma trigonous, papillose. Capsule ovoid to subglobose, 3‒7 mm long, valves completely dehiscing from base; tepals cohering and inrolled above ovary after anthesis, circumcissile from base and persisting as a cap at the top of the developing capsules. Seeds subellipsoid to subtrigonous, flattened with prominent central embryo and wide, flat wings, 2‒5 mm long, black to dark brown, with sinuous anticlinal cell walls.

Number of species and distribution:— Rhadamanthus includes twelve species, occurring in southern and western South Africa and southern Namibia ( Fig. 29 ), and restricted to the Cape, Karoo-Namib and Uzambara-Zululand Regions, and the Southern Section of the Zambezian Subregion (sensu Takhtajan 1986 and Martínez-Azorín et al. 2023a). For further information on Rhadamanthus see Dyer (1934), Nordenstam (1970), Jessop (1977), Martínez-Azorín et al. (2013b), and Manning & Goldblatt (2018).

Karyology:—2n=18 ( Speta 1998a, with no reference). 2n=20 ( De Wet 1957, as Rhadamanthus convallarioides Salisb. ).

History, diagnostic characters, and taxonomic relationships:— Salisbury (1866) described Rhadamanthus to include a single species, Rhadamanthus convallarioides (Linnaeus f. 1782: 204) Salisb. ex Baker (1871: 434) , based on the nodding urceolate to campanulate flowers with the tepals fused for their basal portion, the stamens connivent to the gynoecium and the anthers dehiscing by apical pore-like slits. Baker (1897) described R. cyanelloides Baker (1897: 444) , and later Dyer (1934) described R. urantherus Dyer (1934 : t. 3247), both sharing the peculiar dehiscence of anthers. Nordenstam (1970) presented a revision of Rhadamanthus in which he accepted the previous three species and added six further new species, namely R. albiflorus Nordenstam (1970: 177) , R. arenicola Nordenstam (1970: 166) , R. fasciatus Nordenstam (1970: 174) , R. montanus B.Nord. in Martínez-Azorín & Crespo (2014: 1331), R. platyphyllus B.Nord. in Martínez-Azorín & Crespo (2014: 1332), and R. secundus Nordenstam (1970: 168) . The genus was characterised by the anthers dehiscing incompletely by introrse, longitudinal slits, and it was also reported that in R. fasciatus and R. albiflorus the sutures reached down below the middle of the thecae. In that concept, Rhadamanthus includes a wide range of morphological variation such as bulb scales compact or loose; leaves filiform, numerous and erect or few, wide, flat and appresed to the ground; flowers nodding to patent, stellate to urceolate-campanulate; tepals from nearly free to fused about half of their length; and stamens free or fused along the anthers. Later, Obermeyer (1980a) described two further species, Rhadamanthus namibensis and R. karooicus , and proposed R. subgenus Rhadamanthopsis (here accepted at genus rank), based on the loculicidal anther dehiscence, to seggregate the two latter species from typical Rhadamanthus . Speta (1998b) transferred all nine known species of Rhodocodon , a genus endemic to Madagascar, into Rhadamanthus based on the similarities in flower morphology and anthers dehiscence. However, Knirsch et al. (2015) presented solid morphological and molecular differences and reinstated Rhodocodon . The latest species described in the genus is Rhadamanthus involutus J.C.Manning & Snijman in Snijman et al. (1999: 113).

Martínez-Azorín et al. (2013a) excluded R. cyanelloides as Sagittanthera cyanelloides on the basis of the anthers connate in a cone around the style, among other distinguishing characters. Recently, Manning & Goldblatt (2018) recognised Drimia sect. Rhadamanthus ( Salisbury 1866: 37) Manning & Goldblatt (2018: 129) , including nine species mostly corresponding to the concept of Nordenstam (1970), and followed Martínez-Azorín et al. (2013b) in excluding R. cyanelloides as their monotypic D. sect. Sagittanthera ( Martínez-Azorín et al. 2013a: 46) Manning & Goldblatt (2018: 73) . Even with the exclusion of S. cyanelloides , D. sect Rhadamanthus sensu Manning & Goldblatt (2018) is paraphyletic according to previous studies by Pfosser et al. (2012) and the present one, in which R. platyphyllus and Drimia oliverorum J.C.Manning in Manning & Oliver (2009: 225) are aberrant in the genus in having 1‒2 velutinous leaves that are ovate, flat and adpressed to the ground showing distinct longitudinal furrows, and they form an independent well-supported clade positioned far from the Rhadamanthus clade, a fact that favours acceptance of Striatula to include the latter two species ( Pinter et al. 2019).

The phylogenetic studies by Martínez-Azorín et al. (2023a) include 21 samples that form a well supported clade that is here assimilated to Rhadamanthus , comprising R. arenicola , R. convallarioides , R. fasciatus , R. montanus , R. urantherus together with samples of Urginea ciliata (Linnaeus f. 1782: 199) Baker (1873b: 218) , U. rigidifolia Baker (1878: 323) , U. muirii Brown (1933: 334) , and Drimia cochlearis Mart. -Azorín, M.B.Crespo & A.P.Dold in Martínez-Azorín & Crespo (2014: 1329). The latter four species form a distinct group that is included by Manning & Goldblatt (2018) in D. sect. Sclerophyllae based on their nodding globular buds before anthesis and patent to suberect stellate flowers borne on pedicels longer than tepals, the spreading filaments, and the anthers dehiscing along their entire length. Our phylogenetic results show D. sect. Rhadamanthus sensu Manning & Goldblatt (2018) as paraphyletic without the inclusion of D. sect. Sclerophyllae, which however forms a strongly supported subclade within Rhadamanthus ( Martínez-Azorín et al. 2023a) . We preliminarily include taxa of D. sect. Sclerophyllae in Rhadamanthus , based on the obtained phylogenetic results. Moreover, the stellate flowers with long, spreading stamens of D. sect. Sclerophyllae are atypical for Rhadamanthus s.str., which has short stamens connivent to the gynoecium. However, there exists an apparent transition from flowers of R. albiflorus and R. fasciatus ( Nordenstam 1970) that are subpatent with nearly free and spreading tepals, to the nodding, urceolate flowers of R. arenicola , R. convallarioides , R. secundus , and R. urantherus , with various degrees of tepal connation. In our analyses, three samples of R. fasciatus with sub-stellate flowers form a clade that is sister to the remaining samples and taxa in the genus, indicative of the primitive stage of stellate flowers and early swifts in flower morphology within this lineage. In this sense, Rhadamanthus includes twelve species restricted to South Africa and southern Namibia. No samples of R. albiflorus , R. involutus , and R. secundus were available for the present study. Further studies including a complete sampling in the genus are necessary to evaluate possible alternative classifications within Rhadamanthus .

Accepted species and required new combinations:—

Rhadamanthus albiflorus B. Nord. in Bot. Not. 123: 177 (1970) ≡ Drimia albiflora (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 9: 711 (2000). Type:— SOUTH AFRICA. Western Cape. Bredasdorp (3420): Hesquaspoort , (–AA), elev. 245 m, 20 December 1962, J.P.H. Acocks 23242 (PRE0051091-0! holo.) .

= Rhadamanthus montaguense Oberm. , nom. nud. in sched.: near Montagu Baths, December 1892, H. Bolus 2797 (NBG 72561!).

Rhadamanthus arenicola B. Nord. in Bot. Not. 123: 166 (1970) ≡ Drimia arenicola (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 9: 711 (2000) ( Figs 3.5 , 37.1 ). Type:— SOUTH AFRICA. Northern Cape. Hondeklipbaai (3017): 0.5 miles S of Wallekraal, (–BC), October 1924, Pillans s.n. sub BOL18253 (BOL140332! holo.) .

Rhadamanthus ciliatus (L.f.) Mart.-Azorín, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Ornithogalum ciliatum L.f., Suppl. Pl.: 199 (1782), basionym ≡ Urginea ciliata (L.f.) Baker in J. Linn. Soc., Bot. 13: 218 (1873) ≡ Drimia ciliata (L.f.) J.C.Manning & Goldblatt in Bothalia 33(1): 111 (2003) ( Figs 3.6 , 37.2 ). Type:— SOUTH AFRICA. Caput bonae Spei, Thunberg s.n. (UPS-THUNB [8281] lecto. designated as “ type ” by Jessop in J. S. African Bot. 43: 279. 1977; S-G 79 06 [image!] probl. iso.).

Rhadamanthus cochlearis (Mart.-Azorín, M.B.Crespo & A.P.Dold) Mart.-Azorín, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Drimia cochlearis Mart. - Azorín, M.B.Crespo & A.P.Dold in Taxon 63(6): 1329 (2014), basionym ≡ Drimia cochlearis Mart. - Azorín, M.B.Crespo & A.P.Dold in Syst. Bot. 38(2): 334 (2013), nom. inval. ( Figs 3.7 , 36.3 , 37.3 ). Type:— SOUTH AFRICA. Western Cape, ca. 11 km SW of Calitzdorp, Gamkaberg Nature Reserve (former Groenefontein Nature Reserve), elev. 408 m, 29 September 2011, M. Martínez-Azorín, A.P. Dold, J. Vlok & A. Martínez-Soler MMA941 (GRA holo.: only the bulbs with leaves; ABH iso.).

Rhadamanthus convallarioides (L.f.) Salisb. ex Baker in J. Linn. Soc., Bot. 11: 434 (1871) ≡ Hyacinthus convallarioides L.f., Suppl. Pl.: 204 (1782) ≡ Drimia convallarioides (L.f.) J.C.Manning & Goldblatt in Strelitzia 9: 711 (2000) ( Figs 3.8 , 36.1 , 37.4 ). Type:— SOUTH AFRICA. Northern Cape. Sutherland (3220): karroo below Roggeveld, (–CA), Thunberg s.n. UPS-THUNB8519 (UPS-THUNB! lecto. designated by Nordenstam in Bot. Not. 123: 159. 1970).

Rhadamanthus fasciatus B. Nord. in Bot. Not. 123: 174 (1970) ≡ Drimia fasciata (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 9: 711 (2000) ( Fig. 38.1 ). Type:— SOUTH AFRICA. Northern Cape. Kimberley (2824): Nooitgedacht , c. 10 miles SE of Barkly West, (–DA), elev. c. 3800 ft., 15 October 1960, O.A. Leistner 1983 (PRE0051090-0! holo.; K000257232!, LD iso.) .

Rhadamanthus involutus J.C.Manning & Snijman in Novon 9(1): 113 (1999) ≡ Drimia involuta (J.C.Manning & Snijman) J.C.Manning & Goldblatt in Strelitzia 9: 712 (2000) ≡ Rhadamanthus involutus J.C.Manning & Snijman in Taxon 63: 1330 (2014), nom. superfl. Type:— SOUTH AFRICA. Northern Cape. Calvinia (3119): Arendskraal farm, W of Nieuwoudtville, (–AC), 20 December 1995 flowers, D. Snijman & J.C. Manning 1525 (NBG0158587-0! lecto. designated here: the inflorescence on the upper left hand side corner; K!, MO176399!, PRE0461606-0! isolecto.: only the flowering material).

Comments:—In the light of the recentmost proposal by Mosyakin & McNeill (2022) to amend Art. 8 of the ICN, after which the information in the protologue will rule, and considering that the protologue in Snijman et al. (1999) only indicates a single collecting date (20 December 1995) in the holotype designation, a lectotypification is needed from the mixed type collection NBG0158587-0. Based on the new considerations, the description made by Martínez-Azorín & Crespo (2014: 1330) is therefore nomenclaturally inoperative, since it is either superfluous or not valid.

Rhadamanthus montanus B. Nord. in Taxon 63(6): 1331 (2014) ≡ Rhadamanthus montanus B. Nord. in Bot. Not. 123: 162 (1970), nom. inval. Type:— SOUTH AFRICA. Western Cape. Cape Town (3318): Jonkershoek Twins , (–DD), elev. 3000–4000 ft., 12 February 1945, E. Esterhuysen 11456 (BOL140331! holo.: a bulb with an inflorescence with eight flowers in the upper part; K000257229!, PRE0051072-0!, NBG72562! iso.) .

Rhadamanthus muirii (N.E.Br.) Mart. - Azorín, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Urginea muirii N.E.Br. in Gard. Chron., Ser. 3. 93: 334 (1933), basionym. Type:— SOUTH AFRICA. Near Riversdale , 1933, J. Muir 4846 (K, first-step lecto. designated by Jessop in J. S. African Bot. 43: 315. 1977; second-step lecto. designated here: K000257341!).

Rhadamanthus rigidifolius (Baker) Mart. -Azorín, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Urginea rigidifolia Baker in J. Bot. 16: 323 (1878), basionym ≡ Drimia sclerophylla J.C.Manning & Goldblatt in Strelitzia 9: 712 (2000), nom. nov. [non Drimia rigidifolia Baker in J. Linn. Soc., Bot. 11: 420 (1871) = D. media Jacq. ] ( Figs 3.9 , 38.2 ). Type:— SOUTH AFRICA. Eastern Cape. Graaff-Reinet (3224): Karroo, near Graaff-Reinet, (–BC), elev. 2500 ft., September 1873, H. Bolus 783 (K000257339! lecto. designated as “holo.” by Jessop in J. S. African Bot. 43: 315. 1977).

Rhadamanthus secundus B.Nord. in Bot. Not. 123: 168 (1970) ≡ Drimia secunda (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 9: 712 (2000) ( Fig. 38.3 ). Type:— NAMIBIA. Ļderitz (2615): Ļderitz-Şd, Kovisberge, (–CA), 30 September 1959, W. Giess 2350 (M holo.; PRE 0051080-0!, WIND iso.) .

= Ophioasylon peculiare Dinter , nom. nud. in sched.: NAMIBIA. Bogenfels (2715): Buchuberge, (–DD), 5 July 1929, K. Dinter 6492 (K000257231!, PRE0051078!, SAM).

Rhadamanthus urantherus R.A.Dyer in Hooker’s Icon. Pl. sér. 5, 33: t. 3247 (1934) ≡ Drimia uranthera (R.A.Dyer) J.C.Manning & Goldblatt in Strelitzia 9: 712 (2000) ( Figs 3.10 , 36.2 , 38.4 ). Type:— SOUTH AFRICA. Western Cape. Oudtshoorn (3322): 1 mile E of Oudtshoorn, (–CA), 29 March 1933 [leafing 11 Oct. 1933 ex hort.], Barker s.n. K933/32 (K000257230! lecto. designated by Martínez-Azorín et al. in Phytotaxa 201: 169. 2015 : only the bulb with two inflorescences in centre of sheet).

Figures

FIGURE 3. Seed morphology in Urgineoideae. 1. Rhadamanthopsis hyacinthoides (Baker) Mart.-Azorín et al.; 2. Rhadamanthopsis karooicus (Baker) Mart.-Azorín et al.; 3. Rhadamanthopsis monophyllus (Oberm. ex J.C.Manning & Goldblatt) Mart.-Azorín et al.; 4. Rhadamanthopsis namibensis (Oberm.) Mart.-Azorín et al.; 5. Rhadamanthus arenicola B.Nord.; 6. Rhadamanthus ciliatus (L.f.) Mart.-Azorín et al.; 7. Rhadamanthus cochlearis (Mart.-Azorín et al.) Mart.-Azorín et al.; 8. Rhadamanthus convallarioides (L.f.) Salisb. ex Baker; 9. Rhadamanthus rigidifolius (Baker) Mart.-Azorín et al.; 10. Rhadamanthus urantherus R.A.Dyer; 11. Rhodocodon campanulatus Knirsch et al.; 12. Rhodocodon cryptopodus (Baker) Knirsch et al.; 13. Rhodocodon cyathiformis H.Perrier ex Knirsch et al.; 14. Rhodocodon floribundus H.Perrier ex Knirsch et al.; 15. Rhodocodon graciliscapus Knirsch et al.; 16. Rhodocodon intermedius H.Perrier ex Knirsch et al.; 17. Rhodocodon jackyi Knirsch et al.; 18. Rhodocodon mascarenensis (Baker) Knirsch et al.; 19. Rhodocodon monophyllus Knirsch et al.; 20. Rhodocodon perrieri Knirsch et al. All to the same scale in mm.

FIGURE 29. Approximate distribution ranges of accepted genera in Urgineoideae.

FIGURE 36. Species of Rhadamanthus Salisb. 1. Rhadamanthus convallarioides (L.f.) Salisb. ex Baker from Jacquin (1797: t. 81, as Hyacinthus convallarioides L.f.); 2. Rhadamanthus urantherus R.A.Dyer from Dyer (1934: t. 3247); 3. Rhadamanthus cochlearis (Mart.- Azorín et al.) Mart.-Azorín et al. from Martínez-Azorín et al. (2013: 333, as Drimia cochlearis Mart.-Azorín et al.).

FIGURE 37. Species of Rhadamanthus Salisb. displayed in horizontal rows of images. 1. Rhadamanthus arenicola B.Nord.; 2. Rhadamanthus ciliatus (L.f.) Mart.-Azorín et al.; 3. Rhadamanthus cochlearis (Mart.-Azorín et al.) Mart.-Azorín et al.; 4. Rhadamanthus convallarioides (L.f.) Salisb. ex Baker.

FIGURE 38. Species of Rhadamanthus Salisb. displayed in horizontal rows of images. 1. Rhadamanthus fasciatus B.Nord.; 2. Rhadamanthus rigidifolius (Baker) Mart.-Azorín et al.; 3. Rhadamanthus secundus B.Nord. (Photographs in flower by H. Kolberg); 4. Rhadamanthus urantherus R.A.Dyer.