Distinctive features of Camillea (Xylariaceae) from Cuyabeno as revealed by scanning electron microscopy

Distinctive features of Camillea (Xylariaceae) from Cuyabeno as revealed by scanning electron microscopy

Volume 10, Part 4, November 1996 DISTINCTIVE FEATURES OF CAMILLEA (XYLARIACEAE) FROM CUYABENO AS REVEALED BY SCANNING ELECTRON MICROSCOPY MARGARET WH...

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Volume 10, Part 4, November 1996

DISTINCTIVE FEATURES OF CAMILLEA (XYLARIACEAE) FROM CUYABENO AS REVEALED BY SCANNING ELECTRON MICROSCOPY MARGARET WHALLEY School of Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF The Xylariaceae is a well-known ascomycete wood inhabitants. family with representatives in most parts of the During a two week stay at the Cuyabeno world. Its members are generally described as Nature Reserve, Ecuador, in August 1993 a total stromatic, with unitunicate asci which usually of 119 collections of xylariaceous taxa were made possess an amyloid apical apparatus and have of which 33 were subsequently identified as aseptate ascospores with a germ slit. There are Camillea. The following eight known species a number of deviations from this theme includwere recorded; C. bilabiata Speg., C. cycliscus ing the genus Camillea. Since the Cuyabeno (Mont.) Laessae, J.D. Rogers & Whalley, C. Reserve in Ecuador is well-known for its rich diversity of the Xylariaceae, especially Camillea (Hedger & Gitay, pers. comm.), the British Mycological Society . Expedition provided the opportunity to collect fresh material of Camillea species for study with the electron microscope. Camillea Fr. is a distinctive genus containing over 30 species most of which are confined to the Americas, with a high concentration in the Amazon region. Camillca includes taxa with applanate, discoid or cylindrical stromata which are dark brown or black and are very hard and carbonaceous. (Laes sae, Rogers & Whalley, 1989; San Figs 1-4 Camillea sulcata. Fig 1 Stroma showing radiating furrows. Bar = 1 mm. Fig 2 Detail of Martin Gonzalez & stroma. Bar = 100 !-tm. Fig 3 Tip of furrow (ostiole arrowed). Bar = 10 !-tm. Fig 4 ostiole (arrowed). Rogers, 1992; Whalley, Bar = 10 !-tm. Figs 5-6 Camillea stellata. Fig 5 Stroma. Bar = 1 mm. Fig 6 Details of stroma (osti1995). They are all oles arrowed). Bar = 100 !-tm.



Volume 10, Part 4, November 1996 cyclops (Mont.) Berk. & Curt., C. heterostoma (Mont.) Laessoe, J.D. Rogers & Whalley, C. leprieurii Mont., C. stellata Laessoe, J.D. Rogers & Whalley, C. sulcata (Starb.) Lloyd and C. oerruculospora J.D. Rogers, Laessee & Lodge. In addition C. fusiformis M.A. Whalley has since been described (Whalley, 1995) and a further two taxa are considered to be new but additional material is required before they are formally named. The most frequent taxon found was the dimorphic Camillea leprieurii, occurring mainly as expanded applanate stromata rather than the more distinctive raised, cylindrical form. Camillea cycliscus and C. bilabiata were the next most common taxa. All material was air dried, stored in sealed plastic envelopes with silica gel prior to preparation for electron microscopy. Portions of stroma were mounted using Electrodag (Acheson

Colloids Company), a high conductivity paint, on a 1 em microscope stub. The specimens were coated with a film of gold approximately 500 A thick in a scanning electron microscope coating unit (E 5000 Diode Sputtering System). The coated specimens were then loaded into a Jeol JSM-840 scanning electron microscope for examination. It is the possession of light-coloured ornamented ascospores, apparently lacking a germ slit, which is one of the most distinctive features of the genus. Ascospores usually appear smooth by light microscopy but scanning electron microscopy shows that they are ornamented with warts, spines, pits or poroid reticulations, or are longitudinally ribbed. The nature of the stroma, especially the architecture of the ostioles, together with the distinctive ascospore ornamentation of selected species as observed by scanning electron microscopy, is described here. Stromal and ostiolar form

Figs 7-10 Camillea [usiformis. Fig 7 Raised stroma showing sterile rim surrounding ostiolar depressions. Bar = 1 mm. Fig 8 Ostiolar depressions in stroma. Bar = 100 [lm. Fig 9 Ostiole with plug. Bar = 10 [lffi. Fig 10 Ostiole on sunken projection. Bar = 10 [lm. Figs 11-12 Camillea leprieurii. Fig 11 Stroma of the expanded or 'melanaspis' applanate form. Bar = 1 mm. Fig 12 Detail of stroma showing ostiole. Bar = 100 [lm.

In C. sulcata the stroma is more or less flattened and IS characterized by its remarkable, elongated, radiating furrows (Figs 1-2). The ostioles are inconspicuous and appear as sunken circular pits at the ends of these furrows (Figs 3-4). The collection from Cuyabeno bears a very close resemblance to the illustration of the species given by Miller (1961). Camillea stellata is readily recognised by its peculiar pattern of shallow depressions which are seated on the top of the raised, often conical shaped stroma. These depressions are more or less circular towards the centre of

Volume 10, Part 4, November 1996 the cluster but become ovoid t o wedge-shaped towards the periphery (Fig 5). The ostioles are generally inconspicuous but lie at the outer part of the oval depressions (Fig 6, arrowed). In C. [usiformis the applanate stromata are dotted with a large number of circular depressions, ca 1 mm in diam. with a single ostiole situated in the centre of each depression (Figs 7, 8 & 10). At maturity a plug of tissue which covers the depressions (Fig 9) becomes detached revealing the cen t r al ostiole situated on a sunken projection (Fig 10). In the applanate form of C. leprieurii the ostioles appear as cir- Fig 13 Camillea cyclops. Ascospore with poroid ornamentation. Bar = 1 tJ.m . Fig 14 Camillea bilabicular groups within the ata. Ascospores with poroid ornamentation. Bar = 1 tJ.m. Fig 15 Camillea stellata. Ascospores with longitudinally ribbed ornamentation. Bar = 11Lm. Figs 16-18 Camillea [usiiormis. Fig 16 Ascosp ores central region of the with longitudinally ribbed ornamentation. Bar = 10 lLm. Fig 17 Ascosp ores showing cross-linked flattened stroma (Fig substructure. Bar = 1 tJ.m. Fig 18 Acutel y tapering tip of ascospore. Bar = 1 tJ.m . 11). Each central ostiAcknowledgements ole is surrounded by an annular region which is I wish to convey my thanks to the British bounded by a shallow rim (Fig 12). Mycological Society and especially Dr J. Hedger Ascospore ornamentation and Mr G. Dickson for organising the expedition; to the Catholic University of Quito and, in Although stromal form is distinctive and often particular, Ricardo Viteri for his constant species characteristic it is the ascospore ornaresourcefulness and support ; to Vittoriano, mentation which distinguishes Camillea within Angelina and the Siona-Secoya people for the the family. Thus C. cyclops (Fig 13) and C. bilprivilege of sharing their forest. abiata (Fig 14) exhibit the poroid ornamentation which is the most frequently encountered pattern. In C. stellata (Fig 15) and C. fusiform is References (Figs 16-18) the ornamentation is more elaborate Laessae , T ., Rogers, J .D. & Whalley , A.J .S . (19 89 ) and appears by SEM as a longitudinally ribbed Camillea , J ongiella and light-sp or ed spe cies of ornamentation with an intricate cross-linked Hypoxylon. Mycological Research 93: 121-155. substructure (Figs 17-18). Miller, J.H. (1961) A monograph of the world species of Hypoxylon. University of Georgia Press, Athens, USA. It is a combination of stromal form and San Martin Gonzalez , F . & Rogers, J.D . (199 3) ascospore topography which provides the key Bisc ogniauxia and Camillea in Mexico . Mycotaxon. features for the recognition; without examination 47: 229-258. by scanning electron microscopy these cardinal Whalley, M.A. (1995) Camillea fusiform is sp. nov. from features remain obscure. Ecuador. Syd owia 47: 82-88.

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