Bolusiella iridifolia subsp. picea P.J.Cribb, Kew Bull. 32: 180 (1977).
Heterotypic Synonyms:
Bolusiella lebeliana Delep. & Geerinck, Belg. J. Bot. 130: 135 (1998).
Description:
Epiphytic herbs with non-branching stems, 3-4 mm long, internodes 1 mm long. Leaves deeply sulcate on upper surface, 9-11 x 2 mm, acinaciform, with bilobate apex. Inflorescences 16-23 mm long, 3-6 flowered. Floral bracts broadly triangular, 1.2-3.0 x 1.8-2.5 mm, acuminate apex, dark brown to black, sheathing, and not imbricate in sterile portions of the inflorescence. Flowers 2.1-2.5 mm x 1.1-1.5 mm, 2-3 mm apart from one another. Dorsal sepal widely triangular, 1.3-1.9 x 0.6-1.7 mm. Lateral sepals triangular, 1.7-2.1 x 0.5-1.9 mm, carinate. Petals ovoid, 1.2-1.7 x Q.7-1.0 mm. Lip broadly triangular, 1.3- 1.5 x 0.7—1.3 mm. Spur straight, conical, in the same plane as the lip, 0.5-0.8 mm long and 0.5-0.7 mm diameter. Column 0.7-0.8 mm long. Ovary 1.0—1.8 mm long and 0.3-0.7 mm in diameter.
Etymology:
The name of this subspecies refers to the black colour of its floral bracts.
Habitat:
Epiphytic in humid forests, growing in mosses or lichens, or lithophytic near rivers or waterfalls. The subspecies picea is found at higher elevations than the type subspecies, from 1,300-2,400 m. Flowering peaks in September and in January-April.
Cultivation:
As given for the genus.
Notes:
The choice to recognize this subspecies is justified by the number of morphological characters shared with the nominal subspecies and unique within Bolusiella, such as leaves deeply sulcate on upper surface with a bilobate apex. The only minor distinctive characters are the dark brown to black bracts and the shorter length of the spur. The two subspecies also have distinct distribution and are ecologically separated by an elevational difference: Bolusiella iridiiolia subsp. iridiiolia is usually found at lower elevations than Bolusiella iridiiolia subsp. picea.
Distribution:
Afromontane Region (Kivu-Ruwenzori, Imatongs-Usambara and Uluguru-Mulanje regional mountain systems): Rwanda, Kenya, Burundi, Tanzania, Zambia, Malawi and Zimbabwe.
References:
Burrows, J.E. & Willis, C.K. (eds) (2005). Plants of the Nyika Plateau Southern African Botanical Diversity Network Report No. 31 SABONET, Pretoria Page 317. (Includes a picture): Cribb, P.J. (1977). New orchids from South Central Africa Kew Bulletin 32(1) Pages 178 - 180. (Includes a picture): Kimberley, M.J. (2003). A List of Epiphytic Orchids of Zimbabwe Excelsa 20 Page 49; La Croix, I. & Cribb, P.J. (1998). Orchidaceae (Part 2) Flora Zambesiaca 11(2) Pages 401 - 402. (Includes a picture); La Croix, I. et al. (1983). Malawi Orchids Volume 1 Epiphytic Orchids National Fauna Preservation Society of Malawi Page 38: La Croix, I. et al. (1991). Orchids of Malawi A.A. Balkema, Rotterdam Page 259: Taxonomic revision of the genus Bolusiella (Orchidaceae, Angraecinae) with a new species from Cameroon, Burundi and Rwanda,by Simon Verlynde, Jean-yves Dubuisson, Tariq Stévart, Murielle simo-Droissart, Daniel Geerinck, Bonaventure Sonké, Valérie Cawoy, Pascal Descourvières & Vincent Droissart, Phytotaxa 114 (1): 1-22 (2013); WCSP (2017). 'World Checklist of Selected Plant Families. 24.02-2017; http://apps.kew.org/wcsp/
Images:
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| Habitat/In situ |
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| Photograph©Bart Wursten. Image used with kind permission. |
