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VISCUM congdonii Polh. & Wiens [family VISCACEAE]

Date Updated: 19 August 2007

Herbarium
Royal Botanic Gardens, Kew (K)
Collection
Flora of Tropical East Africa
Resource Type
Reference Sources
Entry From
Flora of Tropical East Africa, page 1, (1999) Author: R. M. Polhill and D. Wiens
Names
VISCUM congdonii Polh. & Wiens [family VISCACEAE], in Novon 7: 278, fig. 2D–E (1997) & Mistletoes Afr.: 302, fig. 36F, 40B (1998). Type: Tanzania, Njombe District, eastern end of Kitulo Plateau, NW. flank of Mtorwi Mt., Wiens, Congdon & Calvin 6985 (K!, holo., BR!, DSM!, EA!, MO!, SRGH!, iso.)
Information
Leafless dioecious relatively large but delicate shrubs, older plants forming long pendulous masses to 2 m.; internodes of distal branches flattened and narrowed, 20–30 mm. long, 1–2 mm. wide. Bracteal cups sessile, short, less than 1 mm. long, often obscured by the subtending leaf-scales. Staminate flowers mostly borne singly, occasionally in dyads or triads, sessile. Pistillate flowers borne singly. Style not evident; stigma somewhat expanded at the summit of the ovary that is gradually elevated from the margin of the tepalar scars. Berries on 1 mm. long pedicels, ellipsoid, 4 mm. high, smooth, orange; tepalar ring-scar 2 mm. in diameter. Fig. 5/6–7 (p. 20).
Range
DISTR. T 7
Altitude range
2150–2350 m.
Distribution
TANZANIA Mbeya District Mporoto Ridge, S. edge of Nshovwi [Chuvwi] Forest Reserve, 1 June 1992, Mwasumbi 16173!;TANZANIA Njombe District eastern end of Kitulo Plateau, NW. flank of Mtorwi Mt., 25 Sept. 1988, Wiens, Congdon & Calvin 6985! & 6987!
Distribution (external)
; Malawi E. Zimbabwe
Notes
The species shows close but superficial similarities to V. goetzei, with which it is associated at the type locality. V. goetzei, however, is an obligate epiparasite known only on Englerina (Loranthaceae) and has a totally different haustorial system from V. congdonii; V. goetzei is also a relatively small erect plant, less than 50 cm. high, whereas V. congdonii is a large pendulous plant up to 2 m. long at maturity. The berries also differ in size, shape, style and stigma characteristics.The collections (mostly sterile) from the high altitude forests of Malawi and Zimbabwe are provisionally placed here, but should be reassessed when more well-collected material is available. There is also an apparently close relationship to V. shirense (see under that species).
VISCUM congdonii Polh. & Wiens [family VISCACEAE]
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