Siphula gracilis
Description : Thallus fruticose, forming pendulous tufts among bryophytes on bark or wood or in mossy grassland growing ±erect. Lobes slender, elongate, discrete, loosely entangled to crowded, flattened to ±subterete, ±evenly tapered, sometimes somewhat twisted, 0.2–1.5(–2) mm wide, (15–)20–60(–75) mm tall, 0.2–0.5 mm thick, simple or sparsely branched (1–3). Surface chalky whitish grey to cream-white, smooth to undulate to scrobiculate, commonly areolate and scabrid, sometimes becoming ±lumpy and mealy; apices blunt, not or very rarely nodulose-lumpy. Margins entire, not thickened or notched. Rhizomorphs pale-brownish, 0.5–1.5 mm thick at point of attachment, terete, densely entangled.
Chemistry : Cortex K+ yellow, C−, KC−, Pd+ weak yellow-orange, UV−; medulla K+ yellow→brownish red, C−, KC−, Pd+ yellow-orange; containing thamnolic acid.
N: South Auckland (Coromandel Ra., Te Aroha, Kaimai Ra.) S: Nelson (Denniston Plateau, Burma Rd), Southland (Henry Saddle Fiordland). On damp soil and among mosses on tree trunks in high-rainfall, subalpine to alpine areas, often intermixed with other species of Siphula (S. decumbens, S. dissoluta, S. fragilis). Known also from W Tasmania (Kantvilas 1998b, 2002a; McCarthy 2003c, 2006).
Australasian
Illustrations : Kantvilas (1998b: 134, fig. 4A–D; 136, fig. 6); Kantvilas & Jarman (1999: 143).
Siphula gracilis (UV–) is characterised by: the terricolous habit; pale ashen-white, slender, delicate and often scabrid lobes; and thamnolic acid in the medulla (K+ yellow→brownish red, C−, KC−, Pd+ yellow-orange). In the Flora account, this species was referred to S. ramalinoides Nyl. ex Cromb (Galloway 1985a: 526), but this latter species is a Chilean endemic occurring from Chiloe to Tierra del Fuego (Kantvilas & Elix 2002: 7–10) and the two species are distinct morphologically and chemically with S. ramalinoides (UV+ whitish) having neothamnolic and lactothamnolic acids (medulla K+ yellow to orange, C− or very weak yellowish, KC+ intense yellow to orange or reddish brown, Pd+ yellow, UV+ whitish) in the medulla, and robust subterete, ±erect lobes that are pale-creamish to beige when fresh.
