AFRICAN

ORCHIDS

Satyrium membranaceum Sw., Kongl. Vetensk. Acad. Nya Handl. 21: 216 (1800).
Heterotypic Synonyms:
Diplecthrum membranaceum Pers., Syn. Pl. 2: 509 (1807).
Satyrium jacottetiae Kraenzl., Vierteljahrsschr. Naturf. Ges. Zürich 64: 102 (1929).
Description:
Plants rather stout to slender, erect, the stems (17-) 23-48 (-57) cm tall. Leaves two, both pressed flat onto the ground, with an abrupt transition to the sheaths above; the longest lamina 2-12 cm long, very broadly ovate-elliptic, obtuse. Sheaths 7-10, mostly dry and membranous at anthesis, set rather closely to the stem, the lower with slightly spreading apices. Inflorescence lax to dense, 5-21 cm long, with (5-) 8-22 (-29) flowers. Perianth pale to quite deep pink, rarely almost white. Scent absent. Bracts mostly dry and membranous distally, gradually becoming deflexed at anthesis, 1,3-1,9 times the length of the 9-18 mm long ovary, the margins glabrous. Sepals and petals fused for 1/4 of their length to the labellum, continuing beyond to form a loose tube by association with the extended sides of the labellum; the sepals with the laterals elliptic acute, the median narrowly oblong, 9-11 mm long; the petals serrulate, the margins crisped, oblong, acute. Labellum from the front as deep as tall, the aperture 5-9 mm high, oblong; the apical flap serrulate and crisped, reflexed, acute, 3 mm high; back of the labellum with a vestigial broad dorsal ridge. Spurs (19-) 21-27 (-29) mm long, standing partly away from the ovary and stem. Column filling the back of the galea, the basal curved part 4-5 mm long. Stigma quadrate to slightly wider distally, 3-4 mm long. Rostellum 3-4 mm long, deeply keeled; the glands varying from lunate and inserted near a rounded rostellum apex, to ovate and deltoid with the rostellum shortly acute. Staminodes as irregular pulvini above the anther sacs.
Habitat:
The altitudes range from 60 m in the Peddie District to over 1600 m on the Katberg, although they are more usually from 200 to 700 m. The plant may be rare to occasional on grassy, open slopes. The variability in the glands and the column apex, properties that are usually highly stable within a species, is remarkable.
Phenology:
Flowering of Satyrium membranaceum takes place in the Spring months from September to November, occasionally as late as December.
Notes:
No clear geographical trend is evident in this, although there is a rather greater concentration of the acute-rostellum form in the Grahamstown area. Colour variation is usually quite limited, from a pale to medium pink; an exception was seen in the Peddie District where the population showed a full range from ivory white to quite deep pink, the latter having rounded apices to the rostellum and clearly distinct from the close ally, Satyrium princeps. In another property, robustness of habit, some local populations of Satyrium membranaceum may approach Satyrium princeps, again remaining clearly distinct from it in other characters.
Distribution:
Its distribution extends from Knysna in the southern Cape to near Cala in Transkei, a distance of about 600 km.
References:
A revision of the southern African species of Satyrium. [A V Hall; Edmund A C L E Schelpe; Nicola C Anthony] 1982 Flora Capensis, Vol 5, Part 3, page 3, (1913) Author: (By R. A. ROLFE.); Molecular Markers Reject Monophyly of the Subgenera of Satyrium (Orchidaceae) Timotheüs van der Niet, Systematic Botany, Vol. 30, No. 2 (Apr. - Jun., 2005), pp. 263-274
Images:
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Habitat/In situ Habitat/In situ Habitat/In situ
Satyrium membranaceum,  01 Satyrium membranaceum,  02 Satyrium membranaceum,  03
Photograph© Cameron
McMaster. Image used
with kind permission.
Photograph© Cameron
McMaster. Image used
with kind permission.
Photograph© Cameron
McMaster. Image used
with kind permission.