Celosia patentiloba C.C.Towns.

Darbyshire, Iain, Burrows, John E., Luke, Quentin & Langa, Clayton, 2022, Cladoceras rovumense sp. nov. (Gentianales-Rubiaceae), a new species from southeast Tanzania and northeast Mozambique, European Journal of Taxonomy 833, pp. 46-59 : 54-55

Celosia patentiloba C.C.Towns.

Hooker’s Icones Plantarum 38: 41, t. 3732 ( Townsend 1975); Flora of Tropical East Africa: 13 ( Townsend 1985).

Type

TANZANIA • Newala ; alt. 670 m [2200 ft]; 9 Apr. 1959; W. Hay 61; holotype: K (2 sheets).

Additional collection studied

MOZAMBIQUE • Cabo Delgado Prov., Mueda District ; 11°31.822ʹ S, 39°26.504ʹ E; alt. 947 m; 10 Sept. 2009; A. Banze 106; K, LMA .

Distribution and habitat

Restricted to the Rovuma CoE, known from the Maconde Plateau of Southeast Tanzania and the Mueda Plateau of northeast Mozambique. It occurs in partial or full shade in woodland including in degraded or disturbed areas, at ca 670–950 m a.s.l. elevation.

Conservation status

This species is currently assessed on the IUCN Red List as Critically Endangered – CR B2ab(iii) – and possibly extinct ( Howard et al. 2020). Whilst the new record from the Mueda Plateau adds a second location, this species could be considered to be severely fragmented given that the two known subpopulations are over 65 km apart, whilst the dispersal potential of this species is likely to be very limited given that it is a small understorey herb. Recolonisation between these isolated subpopulations is, therefore, unlikely to occur. Further, there is very little intact wild habitats still present on both the Maconde and Mueda Plateaux which are highly degraded, with much conversion to agricultural land. At Mueda Plateau, for example, there has been an estimated loss of dense woodland and dry forest vegetation cover of over 96% ( Timberlake et al. 2011). Whilst this species appears tolerant of some disturbance, it is unlikely to persist in farmlands. Furthermore, as noted by Howard et al. (2020), it is possible that the Maconde subpopulation is no longer extant. Therefore, the assessment of CR B2ab(iii) is upheld here.

Taxonomic notes

Two collections from the Rondo Plateau in southeast Tanzania (G.P. Clarke 35; Q. Luke 12958; both K) are closely allied to this species but have markedly smaller perianth segments. These collections may represent a further species of Rovuma CoE endemic in Celosia or possibly a distinct variant of C. patentiloba . Further material is desirable to fully assess the extent of this variation.