Dracaena suffruticosa subsp. longituba Takawira-Nyenya & Thiede
Creators: name: Takawira-Nyenya, Ratidzayi
name: Thiede, Joachim
name: Mucina, Ladislav
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Asparagales
Asparagaceae
Dracaena
Dracaena suffruticosa
Dracaena suffruticosa subsp. longituba (pfennig 1981b: 178) takawira-Nyenya &amp; thiede

description: 14. Dracaena suffruticosa subsp. longituba (Pfennig 1981b: 178) Takawira-Nyenya & Thiede comb. & stat. nov.
Basionym:— Sansevieria suffruticosa var. longituba Pfennig in Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 102: 178 (1981)
Type:— KENYA. Nairobi District: Nairobi River Falls, elev. 1450 m, 14 September 1977, Pfennig 1336 (lectotype, designated here: EA000002615 digital image!, available at: https://plants.jstor.org/stable/history/10.5555/al.ap.specimen.ea000002615; isolectotype: EA000002616 digital image!, available at: https://plants.jstor.org/stable/10.5555/al.ap.specimen.ea000002616).
— Dracaena suffruticosa var. longituba (Pfennig) Byng & Christenhusz (2018: 67).
Note:—The protologue of S. suffruticosa (Brown 1915: 202–203) describes the leaves as “rough throughout or smooth at the basal part and rough above”, the perianth tube “about 5 lin. [= 10.5 mm] long” and cites “ BRITISH EAST AFRICA ” [the territory of Kenya according to the locality today], Nairobi River Falls, scarce, Powell, 13! and without precise locality, Evans s.n.! ”, as syntypes. Pfennig (1981b) found that his cultivated flowering plants and specimens at Kew fell into two discontinuous groups with perianth tube lengths of 9–13 mm and 18–24 mm, with cultivated flowering plants from the type locality of his var. longituba at Nairobi River Falls having perianth tubes 20–24 mm long. Pfennig further concluded that N.E. Brown must have based his protologue on cultivated flowering plants of Evans s.n., and that he had not seen flowering material for the specimen Powell 13. Pfennig could not locate the specimen Powell 13 cited by N.E. Brown at Kew. He described the long-tubed plants which are distributed south of the line Mau Escarpment – Aberdares – Mt. Kenya as S. suffruticosa var. longituba Pfennig (1981b: 178), geographically separated from the short-perianth tubed S. suffruticosa var. suffruticosa distributed north of that line. Newton (2000: 225) added that S. suffruticosa var. longituba has smooth leaves, in contrast to rough leaves in S. suffruticosa var. suffruticosa, a further character separating both taxa which was overlooked by Pfennig. Byng & Christenhusz (2018: 67) transferred this taxon into Dracaena at the rank of variety following the rank assignment of the protologue, but since it differs in two features and is geographically separate, subspecific rank is deemed appropriate.
Typification:—To implement the correct application of the name S. suffruticosa (var. suffruticosa), Mbugua (2007: 26) designated one of the two collections of Evans at Kew; Evans s.n. (17 March 1911, 2 cross-labelled sheets, K 255770 & K 255771 digital images! available at: http://specimens.kew.org/herbarium/K000255770 & http:// specimens.kew.org/herbarium/K000255771) as the lectotype. The specimen Evans s.n. (Oct. 12. 1909, K 000255772 digital image!, available at: http://specimens.kew.org/herbarium/K000255772)) represents a syntype; the syntype Powell 13 is presumed lost (Pfennig 1981b). Newton (2020: 1380) imprecisely cited the “type” as “Evans s.n. [K]”.
The “ holotype ” of S. suffruticosa var. longituba cited in the protologue (Pfennig 1981b: 178) as “ Pfennig 1336 (EA)” consists of two sheets which are not cross-labelled (EA000002615 & EA000002616 see above), thus actually representing syntypes (ICN Article 9.6, Turland et al. 2018). Both sheets consist of a plant with inflorescence and flowers. The specimen EA000002615 which better illustrates the long perianth tube of the flowers is designated here as lectotype.
New synonym
The following recently published infraspecific taxon is referred to the synonymy so that no new combination for its transfer into Dracaena is needed.
description: Published as part of Takawira-Nyenya, Ratidzayi, Thiede, Joachim & Mucina, Ladislav, 2021, New nomenclatural and taxonomic adjustments in Dracaena (Asparagaceae), pp. 293-300 in Phytotaxa 524 (4) on pages 296-297, DOI: 10.11646/phytotaxa.524.4.5, http://zenodo.org/record/5656295