Cyathea rufescens (Mett. ex Kuhn) Domin (1929: 264)

Lehnert, Marcus, 2011, Species of Cyathea in America related to the western Pacific species C. decurrens, Phytotaxa 26, pp. 39-59 : 54-55

34. Cyathea rufescens (Mett. ex Kuhn) Domin (1929: 264) . Hemitelia rufescens Mett. ex Kuhn (1869: 159) . Sphaeropteris rufescens (Mett. ex Kuhn) Windisch (1973: 372) . Type:— PERU. San Martin: Prov. San Martin, “in monte Guayrapurima, prope Tarapoto, Peruviae orientalis,” August 1856, Spruce 4727 (holotype BM, fragment US, isotypes K, fragment US, TCD).

Distribution and habitat: — Peru, San Martin, in mountain rainforest and ridge top vegetation between ca. 1200–1500 m.

Remarks: — Cyathea rufescens is easily recognized by its long triangular segments and easily detached scurf on the laminar axes. With C. macrocarpa , C. macrosora , C. traillii , and C. vaupensis , it shares a special type of narrowly triangular petiole scale, which has rectangular to hook-shaped basal lobes and narrow, fimbriate to ciliate margins.

Cyathea rufescens was long only known from the type collection in northern Peru. The type locality, Mt. Guayarapurina, is not marked on recent maps and most locals have only a faint idea where the mountain might be. In July 2002, M. Christenhusz managed to reach this locus classicus because Spruce’s itinerary gives a fairly good description of its position, and he also collected several specimens of tree ferns there. What I first identified as C. rufescens among these collections, later turned out to be C. pilosissima (Baker) Domin (1929: 263) . In November 2011, I went to Mt. Guayrapurina myself and found Cyathea rufescens still in fair numbers ( Fig. 2 ). It occurs on slopes of mountains adjacent to a fertile plain, and the forest in which it grows evidently yields no valuable timber, so the species seems not directly threatened by human activity. However, the known range is very small and could be easily destroyed by one mayor fire incident. The conservation status of C. rufescens is therefore considered as “endangered” (EN B2a; IUCN 2001).

Figures

FIGURE 2. Trunk morphology. A. Cyathea multiflora, Prov. Pichincha, Ecuador. B–C. Cyathea parvula, Puerto Rico; B. Detail of emerging crosier; C. Detail of persisting spiny petioles on trunk. D. Cyathea leucofolis, Edo. Paraná, Brazil. E. Cyathea boryana, French Guiana. F. Cyathea andina, crosiers only visible after removal of two fronds, Puerto Rico. G–J. Cyathea rufescens, Dept. San Martin, Peru; G. Plant growing on ridge, with several small adventitious plants at the trunk base; H. Detail of frond; J. Trunk apex (A–D, F–J. © Marcus Lehnert, E. © Michel Boudrie).