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A new coelomycete from blighted pine needles in Honduras
568
Notes and brief articles
macronematosa, mononematosa, solitaria vel gregaria, erecta, simplicia, recta vel leniter geniculata, septata, atro-brunnea, apicem versus pallidiora vel brunnea, laevia,ad basim levitertumida, 70-170 Jimlonga, 2' 5-3 Jim crassa. Cellulae conidiogenae monophialidicae, terminales, abrupte angustatae ad 0APffi, collari dilatato, 2-2' 5 pm lato, 1-1' 5 /lm profundo, deinceps proliferatae. Vestigia collarum 3-15 11m distantes lateralia in cellis conidiogenis sympodialiter proliferatis, sub basi in cellis conidiogenis percurrenter proliferatis. Cellulae conidiogenae percurrenter proliferatae ad basim inflatae, 5-6 /lm crassae. Conidia singulatim successive in collari formata, aseptata, hyalina, interdum irregulariter subhyalina vel pallide brunnea, globosa t : 5-2 pm vel subglobosa 1-1'7 x 2-3 11m; ratio lat.jlong. conidiorum 1:1-1:2.
In ligno emortuo, Dullstroorn District, Transvaal, South Africa, April 18, 1983, H. Smith PREM 47375, holotypus. The new species is named in honour of Ms Hester M. Smith, its collector. Colonies broadly effuse, brown to dark brown, hairy. Mycelium mostly immersed in the substrate, composed of branched, septate, subhyaline to pale brown, smooth, 2-2'5 flm wide hyphae. Conidiophores macronematous, mononematous, solitary or in groups, erect, simple, straight or slightly geniculate, septate, dark brown, paler towards the apex to brown, smooth, slightly swollen at the base, 70-17° flmlong, 2'5-3 flm wide. Conidiogenous cells monophialidic, terminal, constricting abruptly to 0' 4 pm and expanding in a flaring collarette, 2-2'5 pm wide, 1-1'5 flm deep, thereafter proliferating. Collarette remnants 3-15 pm apart, lateral on conidiogenous cells which proliferate sympodially, underneath the base on conidiogenous cells which proliferate percurrently. Percurrently proliferating conidiogenous cells swollen at the base, 5-6 11m wide. Conidia produced singly, successively, within the collarette, aseptate, hyaline, occasionally subhyaline to pale brown, globose, 1'5-2 pm to
subglobose 1-1'7 x 2-3 11m; width/length ratio of conidia 1 : 1-1 : 2. Of the known species of Chloridium, C. smithiae is most similar to C. cubense Holubova- Jechova (1982). With C. smithiae, C. cubense is the only other Chloridium described with vestigial collarettes that remain on the conidiophores. C. smithiae differs from C. cubense in that the conidiogenous cell of C. smithiae is constricted abruptly prior to the flaring of the collarette. C. cubense tapers gradually and not to the same extent. The conidial shape also differs markedly between the two species. C. cubense is uniquely triangular whereas C. smithiae is consistently globose to subglobose. Chloridium smithiae defies section placement. The collarette is well-formed with distinct constrictions proximally and has a single conidiogenous locus within, making it unfit for section Chloridium. Proliferation is mostly sympodial, only sometimes percurrent, making Section Gongromeriza sensu stricto unfit. Conidiophores are never produced in two layers and the collarette is never much narrower than the phialide thus eliminating section Psilobotrys as a suitable section. C. smithiae is nonetheless a good Chloridium. This work was supported by research grants from the South African CSIR and the University of Pretoria. Special thanks is given to Mr Paul Hasse for reviewing the Latin diagnosis.
REFERENCES GAMS,
W. & HOLUBovA-JECHovA, V. (1976). Chloridium
and some other dernatiaceous hyphomycetes growing on decaying wood. Studies in Mycology 13. Centraalbureau voor Schimmelcultures, Baarn. 1-48. HOLuBovA-JECHovA, V. (1982). New or interesting phialidic hyphomycetes from Cuba. Mycotaxon 15, 277- 292.
A NEW COELOMYCETE FROM BLIGHTED PINE NEEDLES IN HONDURAS BY H. C. EVANS AND E. PUNITHALINGAM
Commonwealth Mycological Institute, Ferry Lane, Kew, Surrey TW9 ]AF
A new coelomycete species, Ascochytulina pini-acicola, is described and illustrated on diseased primary needles of Pinus maximinoi from the highlands of Honduras. During a pathological survey of the indigenous pine species of Central America (Evans, 1984), an apparently geographically restricted but potentially serious needle blight was discovered on regenerating trees of Pinus maximinoi H. E. Moore in Honduran cloud forest. The suspected causal agent is Trans. Br. mycol. Soc. 84 (3), (1985)
considered to be best accommodated in the coelomycete genus Ascochytulina Petrak. The genus is monotypic (Sutton, 1980) and the pine fungus is sufficiently distinct to warrant its description as a new species.
Printed in Great Britain
Notes and brief articles B
Fig. 1. Ascochytulina pini-acicola on Pinus maximinoi, Honduras, IMI 287057. (A) Vertical section ofpycnidial conidioma; (B) vertical section of deeply convoluted pycnidiurn ; (C) apical, ciypeal (lip) region; (D) pycnidial wall with inner layer of conidiogenous cells and developing conidia; (E) conidiogenous cell and conidia; (F) fragmented conidium. Trans. Br. mycol. Soc. 84 (3), (1985)
Printed in Great Britain
Notes and brief articles
57°
I
3
•
5
Figs
Trans. Br. mycol. Soc. 84 (3), (1985)
2,
3, 4 and 5. For legend see opposite.
Printed in Great Britain
Notes and brief articles Ascochytulina pini-acicola sp.nov. (Figs 1-11) Laesiones initio luteae, fasciatae; rufo-brunnescentes. Mycelium immersum, ramosum, pallide brunneum vel atro brunneum, 2'5-4 pm diarn. Conidiomata pycnidialia, amphigena, separata vel confluenta, nigra, subglobosa vel irregularia, immersa, erumpescentia, unilocularia, convoluta, clypeata, ostiolata, papillata, 250--380 (-450) x 80--125 pID. Paries pycnidialis variabilis: pars apicalis (clypeus) ex 7-10 stratis, cellularum pseudoparenchymatarum (textura globulosa) compositarum; pars dorsalis pallidescens, tenuiescens, 20--30 I,m lata, cellularum isodiametrarum (textura angularis) compositarum. Ostiola rotundata, 15-30 I,m diam, vel irregularia, periphysata, Cellulae conidiogenae enteroblasticae, phialidicae, doliiformes vel ampulliformes, discretae, determinatae, hyalinae, laevesex intimis stratis cellularum cavitatis pycnidii exorientes, 5-8 (-10) x 3'5-5'5 pm. Conidia pallide viridia vel brunnea, laevia, r-septata, raro 3-septata, ad septum non constricta, ellipsoidea vel cylindrica-oblonga, (12-) 14-18 (-20) x 4-5 (-7) pm, saepe curvata, apice rotundata vel obtusa, basi truncata vel rotundata, guttulata.
In foliis vivis Pini maximinoi, Montana San Ildefonso, Sierra de Omoa, Cortes, Honduras, H. C. Evans, 25 April 1983, IMI 287057, holotypus.
Lesions yellow, initially in bands, coalescing and becoming reddish-brown. Mycelium immersed, branched, pale brown, septate, 2' 5-4 Ji.m diam. Conidiomata pycnidial, amphigenous, separate to confluent, up to 3 uniting longitudinally, black, subglobose to irregular, immersed becoming erumpent, unilocular, thick-walled, clypeate, ostiolate, papillate. Pycnidia rupturing the epidermis with a median or lateral linear split, forming linear protrusions along the needle, 250-380 (-450) x 80-125 Jim; individual locules immersed, 160-200 x 220-300 I'm. Ostiole single, circular (15-30 I'm diam) to ovoid or becoming irregular, lined by hyaline periphyses, similar hairs occurring also on the exposed pycnidial wall. Clypeus composed of dark, thick-walled textura globulosa, up to 10 layers or 70 I'm thick, carbonaceous. Pycnidial wall at base consisting of pale-coloured, thin-walled textura angularis, 20-30 p.m wide. Conidiophores absent. Conidiogenous cells formed from the inner layer of cells lining the pycnidial cavity, enteroblastic, phialidic, doliiform to ampulliform, discrete, determinate, hyaline, smooth, 5-8 (-10) x 3'5-5'5 I'm. Conidia pale green to light brown, exuding in a greenish-brown mucilaginous
57 1
cirrhus, smooth, thin-walled, r-euseptate, rarely 3-septate, broadly ellipsoidal or cylindrical to oblong, not constricted at the septum, (12-) 14-18 (-20) x 4-5 (-7) !.tm, often curved, apex rounded to obtuse, base tapered to ±truncate, guttulate.
Teleomorph: Unknown. Cultures: None, no conidial germination on standard agar media. According to the classification proposed by Sutton (1980), the pine fungus is included in the suborder Phialopycnidiineae which on the basis of its pale brown, predominantly r-septate conidia places it near the genera Ascochytulina, Pseudodiplodia (P. Karsten) Sacco and Stenocarpella H. Sydow. The presence of a clypeus and Ascochyta-like conidia excludes it from the latter two genera. However, whereas the clypeus of Ascochytulina defiectens (P. Karsten) Petrak is described and depicted as a loosely-arranged textura intricata, that of the pine fungus is a well-organised structure conforming to the heavily pigmented textura globulosa reported for some Loculoascomycetes of pines (Minter, 1981). Indeed, the ostioles of exceptionally thick-walled, carbonaceous pycnidia tear longitudinally, opening in a manner similar to that of Lophodermium ascostromata. This may reflect the parallel evolution ofa common dehiscence mechanism by obligate pine needle-colonizing fungi. Punithalingam (1979) emended the description of the genus Ascochyta Lib., to include species with either hyaline or pigmented conidia. Nevertheless, the clypeate, thick-walled pycnidia are not characteristic of Ascochyta. It would seem, therefore, that Ascochytulina is the most appropriate genus in which to place the species, at least for the moment until the relationships of this difficult group offungi are resolved. As is evident from Figs 6-8, there is considerable variation in pycnidial morphology particularly the density of the textura globulosa and hence in the degree of differentiation of the clypeus. The markedly convoluted base is a constant characteristic and it is tempting to compare this with conidiomatal structure in the genus Septocyta Petrak. The definition of, and the distinction between, eustromatic and pycnidial conidiomata then becomes difficult to interpret. The hair-like structures lining
Figs 2-5. Ascochytulina pini-acicola. Figs 2-3. Pycnidia on needle surface (x 50). Fig. 2. Dried specimen showing dark, mucilaginous cirrhus (arrows). Fig. 3. Needle mounted in water showing swollen pycnidia and paler-coloured spore column (arrow) emerging from a linear split rather than a circular ostiole. Fig. 4. Apical view of pycnidium, with well-defined circular ostiole and clypeus (x 650). Fig. 5. Conidia around ostiole, note hyaline periphyses (x 1250). Trans. Br. mycol. Soc. 84 (3), (1985)
Primed in Great Britain
Notes and brief articles
57 2
F igs 6, 7, 8, 9,
Tram . B r. mycol. Soc. 84 (3), ( 1985)
10
and
11.
For legend see opposite.
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Notes and brief articles the ostiole are termed here periphyses, although essentially th ey represent sterile conidio geno us cells since they ari se from th e same layer and in the same manner as the latter . The occasional occ urrence of multiseptate conidia was ob serv ed on ly in wh ole pycnidial mounts and not in pr ep arati on s of liberat ed spo res . It is th ought that these are abnormal spo res, not freely relea sed from the con idiogenous cell and hence maturing in situ . The blight sympto ms were so striking in the field and th eir pr esence, on pr imary needles of reg enerating trees in vading an abando ned timber extr act ion road in an isolated area of cloud fore st (ca 1900 m a.s.l.) in th e mountainou s region bordering H onduras and Guatemala, immediately sign alled an unusual di sease. D othistroma needle blight, cause d by Scirrhia (M y cosphaerella) pini Funk & Parker, and its anamorph Dothistroma septospora (D orogu ine) Morelet, had been previously recorded on the same host from this locality , although at slightly lower elevations, 15°0-1 700 a.s.l. (E vans, 1984). H owe ver , the lateral yellowi ng or banding on the needl es and the pr om inent bead-like arrangem ent of pyc nid ia readil y dist ingu ishe s the blight caus ed by A . pini-acicola from the classic red-band disease. On old needl e fascicles a general pink or red co louration develop s distall y and th e necrosis da rkens to a reddish-brown . It is possibl e, therefor e, that this adv ance d stage of infe cti on cou ld be confused in itially with Dothistroma needl e blight. Nevertheless, the symptoms of yellow banding , together with th e pr esence of olive-co loured mucilaginou s cirrhi, are mu ch more likely to be m istaken for Lecanos ticta needle bl ight, cause d by Mycosphaer ella dearnessii Barr and its anamorph Lecanos tict a acicola (T hum .) H. Sydow, ub iqui tous in the pine fore sts of H onduras (Evans, 1984). Ol der necrotic needles were found to be hea vily colonized by sori of a species of th e ru st genus
573
Coleosporium L ev. H owever , all field observations ind icat e th at A . pini- acicola is a primary needle pathogen but with a somewhat re stricted distribution since it was not reco rded from an y other localit y in Centr al America during the aforemention ed pine d isease survey which spanned a 4- year peri od. Pinu s patula Schiede & D eppe su bsp . tecumum an ii St yles commonl y occurs in association with P. ma ximinoi at lower altitudes in th e Omoa range and seed collections from these stands have been made recently (Barn es & St yles, 1983 ; St yles & Hughes, 1983). Ther e is a possibility, th erefore, that A. pini-a cicola ma y be d issem inat ed furth er afield in cont ami nated seed lots and, if so, it could prove to be an important pathogen of exotic pines in warm temperate regions.
This work was carried out within a project (R3410) sponsored by the U.K. Overseas D evelopment Administrati on .
R EFE RENCES
BARNES, R . D . & STYLES, B. T . (1983). The closed -cone pine s of Me xico and Cent ral America. Com monwealth Forestry R ev iew 62 , 81-84. EVANS, H . C. (1984). The gen us Mycosphaere/la and its anamorphs Cercosep toria, D othi str oma and L ecanosticta on pi ne s. Mycological Pap ers 153, 1-1 0 2 . M INTER, D. W . (1981). Lophodermium on pin es. Mycological Papers 147, 1- 54. PUNITHALINGAM, E . (1979). Grarninicolou s Ascochy ta species . Mycological Papers 142, 1-214 . STYLES, B. T . & H UGHES, C. E. (1983). Studies of variatio n in Ce ntral Am er ican pine s. III. No tes on th e taxonom y and nomenclature of the pines and related gymn osp erm s in Hondurasandadja cent Lat in Am er ican Rep ublics. Brenesia 21 , 269-29 1. SUTTON, B. C. (1980). T he Coe lomycetes , K ew : Commo nwealt h My cologica l Institute.
F igs 6-11 . Ascoc hy tu lina pini-acicola, pycnid ial morphology. F igs 6-8 . Variation in struc tur e (all x 208): showing well-developed pycn idium with pr ominent clypeus, not e convol uted base (F ig. 6); similar pycn idium but clypeus poorly differentiated (F ig. 7); p ycn id ium formed at needl e edge or mar gin (F ig. 8). Fig . 9. We ll differentiated clypea l region of textura globulosa ( x 540). F ig.
10 .
L ater al pycn idial wall of tcxtura globulosa showin g inner layer and conid iogenesis ( x 835).
Fig . 11. Basal wall of ligh tly pigmented , th in-walled textura angularis ( x 835). T rans. B r. my col. So c. 84 (3), (1985)
Primed in Gr eat B ritain
Notes and brief articles
macronematosa, mononematosa, solitaria vel gregaria, erecta, simplicia, recta vel leniter geniculata, septata, atro-brunnea, apicem versus pallidiora vel brunnea, laevia,ad basim levitertumida, 70-170 Jimlonga, 2' 5-3 Jim crassa. Cellulae conidiogenae monophialidicae, terminales, abrupte angustatae ad 0APffi, collari dilatato, 2-2' 5 pm lato, 1-1' 5 /lm profundo, deinceps proliferatae. Vestigia collarum 3-15 11m distantes lateralia in cellis conidiogenis sympodialiter proliferatis, sub basi in cellis conidiogenis percurrenter proliferatis. Cellulae conidiogenae percurrenter proliferatae ad basim inflatae, 5-6 /lm crassae. Conidia singulatim successive in collari formata, aseptata, hyalina, interdum irregulariter subhyalina vel pallide brunnea, globosa t : 5-2 pm vel subglobosa 1-1'7 x 2-3 11m; ratio lat.jlong. conidiorum 1:1-1:2.
In ligno emortuo, Dullstroorn District, Transvaal, South Africa, April 18, 1983, H. Smith PREM 47375, holotypus. The new species is named in honour of Ms Hester M. Smith, its collector. Colonies broadly effuse, brown to dark brown, hairy. Mycelium mostly immersed in the substrate, composed of branched, septate, subhyaline to pale brown, smooth, 2-2'5 flm wide hyphae. Conidiophores macronematous, mononematous, solitary or in groups, erect, simple, straight or slightly geniculate, septate, dark brown, paler towards the apex to brown, smooth, slightly swollen at the base, 70-17° flmlong, 2'5-3 flm wide. Conidiogenous cells monophialidic, terminal, constricting abruptly to 0' 4 pm and expanding in a flaring collarette, 2-2'5 pm wide, 1-1'5 flm deep, thereafter proliferating. Collarette remnants 3-15 pm apart, lateral on conidiogenous cells which proliferate sympodially, underneath the base on conidiogenous cells which proliferate percurrently. Percurrently proliferating conidiogenous cells swollen at the base, 5-6 11m wide. Conidia produced singly, successively, within the collarette, aseptate, hyaline, occasionally subhyaline to pale brown, globose, 1'5-2 pm to
subglobose 1-1'7 x 2-3 11m; width/length ratio of conidia 1 : 1-1 : 2. Of the known species of Chloridium, C. smithiae is most similar to C. cubense Holubova- Jechova (1982). With C. smithiae, C. cubense is the only other Chloridium described with vestigial collarettes that remain on the conidiophores. C. smithiae differs from C. cubense in that the conidiogenous cell of C. smithiae is constricted abruptly prior to the flaring of the collarette. C. cubense tapers gradually and not to the same extent. The conidial shape also differs markedly between the two species. C. cubense is uniquely triangular whereas C. smithiae is consistently globose to subglobose. Chloridium smithiae defies section placement. The collarette is well-formed with distinct constrictions proximally and has a single conidiogenous locus within, making it unfit for section Chloridium. Proliferation is mostly sympodial, only sometimes percurrent, making Section Gongromeriza sensu stricto unfit. Conidiophores are never produced in two layers and the collarette is never much narrower than the phialide thus eliminating section Psilobotrys as a suitable section. C. smithiae is nonetheless a good Chloridium. This work was supported by research grants from the South African CSIR and the University of Pretoria. Special thanks is given to Mr Paul Hasse for reviewing the Latin diagnosis.
REFERENCES GAMS,
W. & HOLUBovA-JECHovA, V. (1976). Chloridium
and some other dernatiaceous hyphomycetes growing on decaying wood. Studies in Mycology 13. Centraalbureau voor Schimmelcultures, Baarn. 1-48. HOLuBovA-JECHovA, V. (1982). New or interesting phialidic hyphomycetes from Cuba. Mycotaxon 15, 277- 292.
A NEW COELOMYCETE FROM BLIGHTED PINE NEEDLES IN HONDURAS BY H. C. EVANS AND E. PUNITHALINGAM
Commonwealth Mycological Institute, Ferry Lane, Kew, Surrey TW9 ]AF
A new coelomycete species, Ascochytulina pini-acicola, is described and illustrated on diseased primary needles of Pinus maximinoi from the highlands of Honduras. During a pathological survey of the indigenous pine species of Central America (Evans, 1984), an apparently geographically restricted but potentially serious needle blight was discovered on regenerating trees of Pinus maximinoi H. E. Moore in Honduran cloud forest. The suspected causal agent is Trans. Br. mycol. Soc. 84 (3), (1985)
considered to be best accommodated in the coelomycete genus Ascochytulina Petrak. The genus is monotypic (Sutton, 1980) and the pine fungus is sufficiently distinct to warrant its description as a new species.
Printed in Great Britain
Notes and brief articles B
Fig. 1. Ascochytulina pini-acicola on Pinus maximinoi, Honduras, IMI 287057. (A) Vertical section ofpycnidial conidioma; (B) vertical section of deeply convoluted pycnidiurn ; (C) apical, ciypeal (lip) region; (D) pycnidial wall with inner layer of conidiogenous cells and developing conidia; (E) conidiogenous cell and conidia; (F) fragmented conidium. Trans. Br. mycol. Soc. 84 (3), (1985)
Printed in Great Britain
Notes and brief articles
57°
I
3
•
5
Figs
Trans. Br. mycol. Soc. 84 (3), (1985)
2,
3, 4 and 5. For legend see opposite.
Printed in Great Britain
Notes and brief articles Ascochytulina pini-acicola sp.nov. (Figs 1-11) Laesiones initio luteae, fasciatae; rufo-brunnescentes. Mycelium immersum, ramosum, pallide brunneum vel atro brunneum, 2'5-4 pm diarn. Conidiomata pycnidialia, amphigena, separata vel confluenta, nigra, subglobosa vel irregularia, immersa, erumpescentia, unilocularia, convoluta, clypeata, ostiolata, papillata, 250--380 (-450) x 80--125 pID. Paries pycnidialis variabilis: pars apicalis (clypeus) ex 7-10 stratis, cellularum pseudoparenchymatarum (textura globulosa) compositarum; pars dorsalis pallidescens, tenuiescens, 20--30 I,m lata, cellularum isodiametrarum (textura angularis) compositarum. Ostiola rotundata, 15-30 I,m diam, vel irregularia, periphysata, Cellulae conidiogenae enteroblasticae, phialidicae, doliiformes vel ampulliformes, discretae, determinatae, hyalinae, laevesex intimis stratis cellularum cavitatis pycnidii exorientes, 5-8 (-10) x 3'5-5'5 pm. Conidia pallide viridia vel brunnea, laevia, r-septata, raro 3-septata, ad septum non constricta, ellipsoidea vel cylindrica-oblonga, (12-) 14-18 (-20) x 4-5 (-7) pm, saepe curvata, apice rotundata vel obtusa, basi truncata vel rotundata, guttulata.
In foliis vivis Pini maximinoi, Montana San Ildefonso, Sierra de Omoa, Cortes, Honduras, H. C. Evans, 25 April 1983, IMI 287057, holotypus.
Lesions yellow, initially in bands, coalescing and becoming reddish-brown. Mycelium immersed, branched, pale brown, septate, 2' 5-4 Ji.m diam. Conidiomata pycnidial, amphigenous, separate to confluent, up to 3 uniting longitudinally, black, subglobose to irregular, immersed becoming erumpent, unilocular, thick-walled, clypeate, ostiolate, papillate. Pycnidia rupturing the epidermis with a median or lateral linear split, forming linear protrusions along the needle, 250-380 (-450) x 80-125 Jim; individual locules immersed, 160-200 x 220-300 I'm. Ostiole single, circular (15-30 I'm diam) to ovoid or becoming irregular, lined by hyaline periphyses, similar hairs occurring also on the exposed pycnidial wall. Clypeus composed of dark, thick-walled textura globulosa, up to 10 layers or 70 I'm thick, carbonaceous. Pycnidial wall at base consisting of pale-coloured, thin-walled textura angularis, 20-30 p.m wide. Conidiophores absent. Conidiogenous cells formed from the inner layer of cells lining the pycnidial cavity, enteroblastic, phialidic, doliiform to ampulliform, discrete, determinate, hyaline, smooth, 5-8 (-10) x 3'5-5'5 I'm. Conidia pale green to light brown, exuding in a greenish-brown mucilaginous
57 1
cirrhus, smooth, thin-walled, r-euseptate, rarely 3-septate, broadly ellipsoidal or cylindrical to oblong, not constricted at the septum, (12-) 14-18 (-20) x 4-5 (-7) !.tm, often curved, apex rounded to obtuse, base tapered to ±truncate, guttulate.
Teleomorph: Unknown. Cultures: None, no conidial germination on standard agar media. According to the classification proposed by Sutton (1980), the pine fungus is included in the suborder Phialopycnidiineae which on the basis of its pale brown, predominantly r-septate conidia places it near the genera Ascochytulina, Pseudodiplodia (P. Karsten) Sacco and Stenocarpella H. Sydow. The presence of a clypeus and Ascochyta-like conidia excludes it from the latter two genera. However, whereas the clypeus of Ascochytulina defiectens (P. Karsten) Petrak is described and depicted as a loosely-arranged textura intricata, that of the pine fungus is a well-organised structure conforming to the heavily pigmented textura globulosa reported for some Loculoascomycetes of pines (Minter, 1981). Indeed, the ostioles of exceptionally thick-walled, carbonaceous pycnidia tear longitudinally, opening in a manner similar to that of Lophodermium ascostromata. This may reflect the parallel evolution ofa common dehiscence mechanism by obligate pine needle-colonizing fungi. Punithalingam (1979) emended the description of the genus Ascochyta Lib., to include species with either hyaline or pigmented conidia. Nevertheless, the clypeate, thick-walled pycnidia are not characteristic of Ascochyta. It would seem, therefore, that Ascochytulina is the most appropriate genus in which to place the species, at least for the moment until the relationships of this difficult group offungi are resolved. As is evident from Figs 6-8, there is considerable variation in pycnidial morphology particularly the density of the textura globulosa and hence in the degree of differentiation of the clypeus. The markedly convoluted base is a constant characteristic and it is tempting to compare this with conidiomatal structure in the genus Septocyta Petrak. The definition of, and the distinction between, eustromatic and pycnidial conidiomata then becomes difficult to interpret. The hair-like structures lining
Figs 2-5. Ascochytulina pini-acicola. Figs 2-3. Pycnidia on needle surface (x 50). Fig. 2. Dried specimen showing dark, mucilaginous cirrhus (arrows). Fig. 3. Needle mounted in water showing swollen pycnidia and paler-coloured spore column (arrow) emerging from a linear split rather than a circular ostiole. Fig. 4. Apical view of pycnidium, with well-defined circular ostiole and clypeus (x 650). Fig. 5. Conidia around ostiole, note hyaline periphyses (x 1250). Trans. Br. mycol. Soc. 84 (3), (1985)
Primed in Great Britain
Notes and brief articles
57 2
F igs 6, 7, 8, 9,
Tram . B r. mycol. Soc. 84 (3), ( 1985)
10
and
11.
For legend see opposite.
Primed in Great B ritain
Notes and brief articles the ostiole are termed here periphyses, although essentially th ey represent sterile conidio geno us cells since they ari se from th e same layer and in the same manner as the latter . The occasional occ urrence of multiseptate conidia was ob serv ed on ly in wh ole pycnidial mounts and not in pr ep arati on s of liberat ed spo res . It is th ought that these are abnormal spo res, not freely relea sed from the con idiogenous cell and hence maturing in situ . The blight sympto ms were so striking in the field and th eir pr esence, on pr imary needles of reg enerating trees in vading an abando ned timber extr act ion road in an isolated area of cloud fore st (ca 1900 m a.s.l.) in th e mountainou s region bordering H onduras and Guatemala, immediately sign alled an unusual di sease. D othistroma needle blight, cause d by Scirrhia (M y cosphaerella) pini Funk & Parker, and its anamorph Dothistroma septospora (D orogu ine) Morelet, had been previously recorded on the same host from this locality , although at slightly lower elevations, 15°0-1 700 a.s.l. (E vans, 1984). H owe ver , the lateral yellowi ng or banding on the needl es and the pr om inent bead-like arrangem ent of pyc nid ia readil y dist ingu ishe s the blight caus ed by A . pini-acicola from the classic red-band disease. On old needl e fascicles a general pink or red co louration develop s distall y and th e necrosis da rkens to a reddish-brown . It is possibl e, therefor e, that this adv ance d stage of infe cti on cou ld be confused in itially with Dothistroma needl e blight. Nevertheless, the symptoms of yellow banding , together with th e pr esence of olive-co loured mucilaginou s cirrhi, are mu ch more likely to be m istaken for Lecanos ticta needle bl ight, cause d by Mycosphaer ella dearnessii Barr and its anamorph Lecanos tict a acicola (T hum .) H. Sydow, ub iqui tous in the pine fore sts of H onduras (Evans, 1984). Ol der necrotic needles were found to be hea vily colonized by sori of a species of th e ru st genus
573
Coleosporium L ev. H owever , all field observations ind icat e th at A . pini- acicola is a primary needle pathogen but with a somewhat re stricted distribution since it was not reco rded from an y other localit y in Centr al America during the aforemention ed pine d isease survey which spanned a 4- year peri od. Pinu s patula Schiede & D eppe su bsp . tecumum an ii St yles commonl y occurs in association with P. ma ximinoi at lower altitudes in th e Omoa range and seed collections from these stands have been made recently (Barn es & St yles, 1983 ; St yles & Hughes, 1983). Ther e is a possibility, th erefore, that A. pini-a cicola ma y be d issem inat ed furth er afield in cont ami nated seed lots and, if so, it could prove to be an important pathogen of exotic pines in warm temperate regions.
This work was carried out within a project (R3410) sponsored by the U.K. Overseas D evelopment Administrati on .
R EFE RENCES
BARNES, R . D . & STYLES, B. T . (1983). The closed -cone pine s of Me xico and Cent ral America. Com monwealth Forestry R ev iew 62 , 81-84. EVANS, H . C. (1984). The gen us Mycosphaere/la and its anamorphs Cercosep toria, D othi str oma and L ecanosticta on pi ne s. Mycological Pap ers 153, 1-1 0 2 . M INTER, D. W . (1981). Lophodermium on pin es. Mycological Papers 147, 1- 54. PUNITHALINGAM, E . (1979). Grarninicolou s Ascochy ta species . Mycological Papers 142, 1-214 . STYLES, B. T . & H UGHES, C. E. (1983). Studies of variatio n in Ce ntral Am er ican pine s. III. No tes on th e taxonom y and nomenclature of the pines and related gymn osp erm s in Hondurasandadja cent Lat in Am er ican Rep ublics. Brenesia 21 , 269-29 1. SUTTON, B. C. (1980). T he Coe lomycetes , K ew : Commo nwealt h My cologica l Institute.
F igs 6-11 . Ascoc hy tu lina pini-acicola, pycnid ial morphology. F igs 6-8 . Variation in struc tur e (all x 208): showing well-developed pycn idium with pr ominent clypeus, not e convol uted base (F ig. 6); similar pycn idium but clypeus poorly differentiated (F ig. 7); p ycn id ium formed at needl e edge or mar gin (F ig. 8). Fig . 9. We ll differentiated clypea l region of textura globulosa ( x 540). F ig.
10 .
L ater al pycn idial wall of tcxtura globulosa showin g inner layer and conid iogenesis ( x 835).
Fig . 11. Basal wall of ligh tly pigmented , th in-walled textura angularis ( x 835). T rans. B r. my col. So c. 84 (3), (1985)
Primed in Gr eat B ritain