ADDITIONAL SPECIMENS EXAMINED: NORTH ISLAND: AUCKLAND: Waitakere Ranges, Fairy Falls Track, on Rhopalostylis sapida, 12 Aug 1981, G. J. Samuels, P. R. Johnston, R. E. Beever, R. P. Korf, & J. W. Paden, PDD 42073; Waitakere Ranges, Fairy Falls Trail, on Rhopalostylis sapida, 25 Jan 1980, G. J. Samuels & W. B. Kendrick, PDD 49625, anamorph on host; Waitakere Ranges, Fairy Falls Trail, on Rhopalostylis sapida, 7 May 1981,G. J. Samuels, P. R. Johnston&E. Horak, PDD 45719, culture on CMD; Waitakere Ranges, Fairy Falls Trail, on Rhopalostylis sapida, 27 Apr 1983, G. J. Samuels, P. R. Johnston, & R. H. Petersen, PDD 45782; Waitakere Ranges, Cascades, on Rhopalostylis sapida, 9 Mar 1981, G. J. Samuels & P. R. Johnston, PDD 49599, anamorph on host; Waitakere Ranges, Kauri Grove Trail, on Rhopalostylis sapida, 1 Jul 1980, G. J. Samuels & P. R. Johnston, PDD 49658, culture on OA; Waitakere Ranges, Kauri Grove Trail, on Rhopalostylis sapida, 1 Jul 1980, G. J. Samuels & P. R. Johnston, PDD 49659, culture on OA. NORTHLAND: Hokianga Co., Waipoua State Forest, between Forest Headquarters and a point c. 1.2 hr walk N of headquarters along Yakas Track, on Rhopalostylis sapida, 30 May 1982, G. J. Samuels, R. H. Petersen, A. P. Hawthorne, & P. R. Johnston, PDD 43199, anamorph on host; Hokianga Co., Waipoua State Forest, Kauri Ricker Track, on sheathing base of Rhopalostylis sapida, 22 Jun 1981, G. J. Samuels, R. H. Petersen, A. P. Hawthorne, & P. R. Johnston, PDD 41981. SOUTH ISLAND: BULLER: Karamea, Kohaihai, Nikau Walk, on Rhopalostylis sapida, 11 May 1994, P. R. Johnston, PDD 66226.

Subiculum evanescent, restricted in extension approx. 2-6 x 1-2 mm, in white, cream, to light brown patches, bearing conidiophores, covering stromatal initials, subsequently reduced while stromata progressively emerge and eventually confined to stromatal margins until absent in old material. Stromata (225)507 ± 112(825) µm high, (375)628 ± 107(875) µm wide (n = 60), semiglobose, cupulate to conical, black, smooth, shiny, adhering to the substrate with a flat ring composed of hard stromatic material, solitary or in small groups on a common stromatic layer, occasionally containing more than one perithecium. Young stromata covered by a cream to light brown to grey, felty, hyphal mat, progressively emerging during development until completely free at maturity. Ostioles finely papillate, sometimes minimally pronounced. Ectostroma 25-50 µm thick, hard, splintering. Entostroma not seen. Perithecia detached and collapsed in older material, located in the centre of cavity. Ascus apical rings (1.9)2.3 ± 0.4(2.8) long, upper width 2-3.6 µm, lower width 1.5-2 µm (n = 26), without bulge at upper margin, J+, pale blue. Ascospores (10.5)13 ± 0.8(15.4) µm long, (4.3)6 ± 0.5(10.5) wide (n = 290), ellipsoidal, brown, with straight germ slit extending the whole spore length or ending shortly before. Conidia 3.5- 5.5 x 2.5-3.5 µm.
Cultures on OA after 33 days at 20°C under 12 h dark and 12 h UV and fluorescent light (2.5)6- 6.5 cm diam., velvety from short hyphae, dense, felty, white to tan, light grey in the centre, restricted grey pustules with conidiophores. Conidiophores up to 200 µm long, 3 µm wide, mononematous, macronematous, erect, irregularly dichotomously branched, smooth, pale tan. Conidiogenous cells 9- 28 x 3 µm (n = 28), terminal or integrated, cylindrical, geniculate with circular refractive frill,1 µm diam., at each point of conidial dehiscence. Conidia (2.5)3-5 x 2-3(4) µm (n = 44), subglobose to obovate, with flat, protuberant, c. 1 µm wide base bearing a refractive ring, smooth, subhyaline to pale tan. On CMD after 21 days under same conditions 2 cm diam., transparent, light grey-tan, with erect, short, much branched aerial hyphae, conidial production poor, restricted to few scattered tufts. Conidiophores variable in length, more than 150 µm, repeatedly branched, without main axis, smooth, subhyaline to pale tan. Conidiogenous cells variable in length, 2-3 µm wide, cylindrical, geniculate terminal, rarely intercalary with circular refractive frill at each point of conidial dehiscence. Conidia 3.5-5 x 2.5-3.5 µm (n = 22), subglobose to clavate, with flat, protuberant, base bearing a refractive ring, smooth, subhyaline to pale tan.
ANAMORPH: Geniculosporium.

HOSTS: Rhopalostylis sapida.
MATRIX: Pieces of rachides.

Subiculum evanescens, restrictum extensione 2-6 x 1-2 mm, album, cremeum ad pallide brunneum, conidiophora ferens. Stromata (225)507 ± 112(825) µm alta, (375)628 ± 107(875) µm lata, semiglobosa ad cupulata, nigra, nitida, substrato ope disci applanati maeriale stromatico compositi adhaerentia, solitaria vel in parvis gregibus stromatico strato insitis conferta, interdum plus quam unum perithecium continentia. Ostiola laeviter papillata, interdum parum evoluta. Annulus apicalis asci (1.9)2.3 ± 0.4(2.8) µm altus, parte superiore 2- 3.6 µm et inferiore 1.5-2 µm latus, margine superiore non protuberanti, iodo pallide coerulescenti. Ascosporae (10.5)13 ± 0.8(15.4) µm longae, (4.3)6 ± 0.5(10.5) µm latae, ellipsoideae, brunneae, fissura germinativa recta, ad totam ascosporam recurrenti vel paululo breviter praeditae. Status anamorphosis Geniculosporium.

ETYMOLOGY: Referring to the most frequent host, Rhopalostylis.
NOTES: Rosellinia rhopalostilicola has black, shiny stromata covered by a cream to light brown subiculum when young. It differs from R. johnstonii by apically rounded stromata, larger ascospores, and a symmetrical germ slit; from R. mammoidea by cupulate stromata with more pronounced ostioles, ascospores without a cellular appendage, and a germ slit extending the whole spore length; and from R. communis by stromatal shape and much smaller ascospores. It can be distinguished from R. subiculata by the subiculum colour and larger ascospores (Petrini 1993).
The presence of a subiculum in young stages as well as the Geniculosporium anamorph justify placement of this species in Rosellinia. Mature specimens without subiculum might be confused with Astrocystis spp. at first sight, because they occur on palm and most species of Astrocystis are described from such hosts (Smith & Hyde 2001). The stromata of R. rhopalostilicola, however, show the regular nearly cupulate shape of typical Rosellinia and have well-pronounced papillate ostioles and the surface is smooth and shiny, without traces of a splitted stroma or adhering host material. Rosellinia euterpes Rehm, also described from a palm, has wider, semiglobose, opaque stromata with less pronounced ostioles, smaller ascus apical rings and smaller ascospores than R. rhopalostilicola

HOLOTYPUS (hic designatus): New Zealand, North Island, Northland, Waipoua Forest, trail between Yakas Kauri and Forest Headquarters, onRhopalostylis sapida, 24 Jun 1981, G. J. Samuels, A. P. Hawthorne, E. Horak, & R. Petersen, PDD 49441.