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Studies on fungi in coastal soils
Trans. Brit. mycol. Soc. 47 (2), 263-267 (1964)' Printed in Great Britain
STUDIES ON FUNGI IN COASTAL SOILS V. DENDRYPHIELLA SALINA (SUTHERLAND) COMB.NOV.
By G. J. F. PUGH
Department of Botany, University of Nottingham AND
JACQUELINE NICOT
Laboratoire de Cryptogamie, Museum National d'Histoire Naturelle, Paris (With 3 Text-figures) The taxonomic position of Cercospora salina, a common saprophyte in intertidal regions, is considered, and genera in which it might be included discussed. The species appears to fit best into Dendryphiella, and is transferred as D. salina (Sutherland) comb. nov.
The distribution records of Cercospora salina show it to be widespread in intertidal regions (Sutherland, 1916; Wilson, 1951; Pugh, 1962) and to occur in the sea, where it has been recorded on submerged wood blocks (Jones, 1962). The same uniformity is not to be found when dealing with the taxonomy ofthis species. Even Sutherland (1916) in his original description stated 'When grown on dry material above tide mark, the dark, stout thick-walled conidia might be regarded as belonging to Helminthosporium, but the type and habitat of conidiophore, as well as the arrangement of conidia is distinctly that of Cercospora.' Chupp (1953) in his monograph ofthe genus, examined the material at Kew and found that the conidia were distinctly echinulate. He stated that it was not a Cercospora, but considered that it might be a Heterosporium. He asserted that species of Cercospora were never wholly saprophytic, though they often accompany or follow other fungi. Pugh (1962) and Dr I. M. Wilson (pers. comm.) and others have not been satisfied that this species is a good Cercospora, but the problem of where it best fitted was not easy to solve. In addition to Cercospora itself, the genera which have been considered are Alternaria, Dendryphiella, Dendryphion, Helminthosporium and Heterosporium. As the conidia of C. salina are produced at pores in the wall of the conidiophore, this species appears to fit into Section VI of Hughes's (1953) classification, and therefore Cercospora and Heterosporium, placed in Section II, are excluded from consideration. In Section VI Hughes placed Alternaria spp., some species of Helminthosporium, and Dendryphion, with which he merged Dendryphiella. Helminthosporium is excluded because, although its conidia may be produced in heads on the conidiophore, they are not produced in chains, while Alternaria is excluded because of the generally muriform character of its conidia. However, it must be mentioned that a very occasional conidium of Cercospora salina with a single vertical septum has been seen. Dendryphion and Dendryphiella are distinguishable from each other by
Transactions British Mycological Society
264
looser and longer branching of the conidiophore in Dendryphiella, though Hughes (1953) did not regard these differences as sufficient to justify retaining Dendryphiella. Nicot (1958) disagreed with this viewpoint when she described, as D. armaria, a new sand-inhabiting hyphomycete. Cercospora salina has some similarities with both genera as at present recognized. The conidiophores are generally short, simple or occasiunally
1,!
I
30/4
Fig.
I.
Dendryphiella inurseminata. (Fig. 9 of Ellis et al. 1951.) A-G, in culture on potato dextrose agar; H, germinating conidia.
branched, with the conidia forming on slightly swollen apical or intercalary cells. The conidia, which are 3-(5)-7 septate and smooth-walled, often form short chains, though longer chains of up to ten conidia have infrequently been observed. Dendryphion is characterized by a definite, erect, closely branched conidiophore upon which chains of multiseptate smooth conidia develop, whereas Dendryphiella possesses a much more lax conidiophore, and usually three-septate, somewhat roughened conidia described as verruculose in D. interseminata by Ellis, Ellis & Ellis (1951)
Fungi in coastal soils. V. G. J. F. Pugh and J. Nicot
265
and' faiblement echinulee ' in D. arenaria by Nicot (1958). The formation of these conidia in short chains might raise some doubts about placing any of these species in Dendryphiella as the original description of the genus says that the spores are not formed in chains ('nicht kettenformig', Bubak & Ranojevic, in Ranojevic, 1914). However, in culture the type species does produce short chains of conidia.
····ca
·c ep -en
e
-
10/-,
Fig. 2. Dendryphiella arenaria. (Fig. I of Nicot, 1958.) a, Aspect de l'appareil conidien; b, spores mures ; c, detail des conidiophores; formation des spores; d, spores en voie de germination; e, detail des parois d'une spore vue en coupe optique;f, spores d'une culture sur milieu it 3,4% de NaC!. (a et dx 700; b, c,fx 1,100; e, schematique.)
Cercospora salina and Dendryphiella arenaria possess many features in common, ecologically, physiologically and morphologically. Both occur in coastal regions subjected to inundation by the sea, and both are able to grow well in media to which NaGl has been added. Maximum increase in colony diameter of the former at 25° G. occurred between 1 and 2 % NaGl; at 3'2 % it grew at the same rate as a colony without added salt, and at 10 % salt (the upper limit used) it still produced active growth. D. arenaria, as shown by Nicot (1958), attained the same colony diameter 17
Myc. 47
266
Transactions British Mycological Society
at 3'4 % NaCI as a control culture without added salt, and th e amount of gro wth gradually decreased up to 20 % salt (the maximum used ). On the saline medi a D. armaria appeared to produce smooth-walled conidia, many of which were 5-scptatc. Morphologically the conidiophores of both species arc very similar, as is the method of spore formation at pores and the production of conidia in short chains which may branch.
2
"
,
Fig. 3. Dendryphiellasalina. (Cncospora salina, Fig. 4 of Sutherland, 1916.) I , Cr eeping my celium with types of erect conidiophores ; 2, de veloping conidia ; 3, types of conidia; 4, germination of conidium showing immediate development of long , narrow type in salt water; 5, development of cell masses.
Consequently, these two species are regarded as being congeneric, and they have some features of both Dendryphion and Dendryphiella. Among the criteria to be evaluated in making a decision between these genera are the form of the conidiophore, the degree of septation of the conidia, and the texture of the conidial wall. The morphology of the diffuse conidiophore has been adopted as th e primary character, because the conidia of D. arenaria have be en shown to be very variable on media containing salt. Dendryphiella appears to be the more suitable genus for Cercospora salina, and this species is therefore transferred as D. salina (Sutherl and ) comb.nov. (basionym C. salina Sutherland in New Phytol. 15, p. 43, 1916) . The three species of Dendryphiella are easily distinguishable from each other. D . inierseminata has an erect conidiophore 210-300 It long, bearing mainly three-septate conidia 16-25 (21) x 6--B (7),U . (Ellis et al. 1951 ). In D. armaria the conidiophores may be 15-25# long, or much longer
Fungi in coastal soils. V. G.]. F. Pugh and]. Nicot
267
(80-go JL), bearing predominantly three-septate conidia 13-20 (15-17) x 4'5-6'5 (5"6) JL and also smaller r-septate conidia 10-15 (12- 14) x 3'55"5ft (Nicot, Ig58). The conidiophores of D. salina vary between I5-60ft, and generally resemble the shorter conidiophores of D. arenaria. Conidia are predominantly 3-5 septate, 20-45 x 6-g JL, with longer, 5-7 septate conidia, 45-70 x 6-9 JL (Pugh, 1962). We would like to thank Dr M. B. Ellis for most helpful discussions. REFERENCES
CHUPP, C. (1953). A monograph qfCercospora. Cornell University, Ithaca, N.Y. ELLIS, M. B., ELLIS, E. A. & ELLIS, J. P. (1951). British marsh and fen fungi. Trans. Brit. mycol, Soc. 34, 147-169. HUGHES, S. J. (1953). Conidiophores, conidia and classification. Ganad.]. Bot. 3 1 , 577659· JONES, E. B. G. (1962). Marine fungi. Trans. Brit. mycol. Soc. 45, 93-114. NICOT, J. (1958). Une moisissure arenicole du littoral atlantique: Dendryphiella arenaria sp.nov. Rev. Mycol., Paris, 23, 87-99. PUGH, G. J. F. (1962). Studies on fungi in coastal soils. 1. Cercospora salina Sutherland. Trans. Brit. mycol. Soc. 45, 255-260. RANOJEVIC, N. (1914). Dritter Beitrag zur Pilzflora Serbiens. Ann. mycol., Berl., 12, 393-421. SUTHERLAND, G. K. (1916). Marine Fungi Imperfecti. New Phytol. 15, 35-48. WILSON, 1. M. (1951). Notes on some marine fungi. Trans. Brit. mycol. Soc. 34, 540-543.
(Accepted for publication 18 November 1963)
17-2
STUDIES ON FUNGI IN COASTAL SOILS V. DENDRYPHIELLA SALINA (SUTHERLAND) COMB.NOV.
By G. J. F. PUGH
Department of Botany, University of Nottingham AND
JACQUELINE NICOT
Laboratoire de Cryptogamie, Museum National d'Histoire Naturelle, Paris (With 3 Text-figures) The taxonomic position of Cercospora salina, a common saprophyte in intertidal regions, is considered, and genera in which it might be included discussed. The species appears to fit best into Dendryphiella, and is transferred as D. salina (Sutherland) comb. nov.
The distribution records of Cercospora salina show it to be widespread in intertidal regions (Sutherland, 1916; Wilson, 1951; Pugh, 1962) and to occur in the sea, where it has been recorded on submerged wood blocks (Jones, 1962). The same uniformity is not to be found when dealing with the taxonomy ofthis species. Even Sutherland (1916) in his original description stated 'When grown on dry material above tide mark, the dark, stout thick-walled conidia might be regarded as belonging to Helminthosporium, but the type and habitat of conidiophore, as well as the arrangement of conidia is distinctly that of Cercospora.' Chupp (1953) in his monograph ofthe genus, examined the material at Kew and found that the conidia were distinctly echinulate. He stated that it was not a Cercospora, but considered that it might be a Heterosporium. He asserted that species of Cercospora were never wholly saprophytic, though they often accompany or follow other fungi. Pugh (1962) and Dr I. M. Wilson (pers. comm.) and others have not been satisfied that this species is a good Cercospora, but the problem of where it best fitted was not easy to solve. In addition to Cercospora itself, the genera which have been considered are Alternaria, Dendryphiella, Dendryphion, Helminthosporium and Heterosporium. As the conidia of C. salina are produced at pores in the wall of the conidiophore, this species appears to fit into Section VI of Hughes's (1953) classification, and therefore Cercospora and Heterosporium, placed in Section II, are excluded from consideration. In Section VI Hughes placed Alternaria spp., some species of Helminthosporium, and Dendryphion, with which he merged Dendryphiella. Helminthosporium is excluded because, although its conidia may be produced in heads on the conidiophore, they are not produced in chains, while Alternaria is excluded because of the generally muriform character of its conidia. However, it must be mentioned that a very occasional conidium of Cercospora salina with a single vertical septum has been seen. Dendryphion and Dendryphiella are distinguishable from each other by
Transactions British Mycological Society
264
looser and longer branching of the conidiophore in Dendryphiella, though Hughes (1953) did not regard these differences as sufficient to justify retaining Dendryphiella. Nicot (1958) disagreed with this viewpoint when she described, as D. armaria, a new sand-inhabiting hyphomycete. Cercospora salina has some similarities with both genera as at present recognized. The conidiophores are generally short, simple or occasiunally
1,!
I
30/4
Fig.
I.
Dendryphiella inurseminata. (Fig. 9 of Ellis et al. 1951.) A-G, in culture on potato dextrose agar; H, germinating conidia.
branched, with the conidia forming on slightly swollen apical or intercalary cells. The conidia, which are 3-(5)-7 septate and smooth-walled, often form short chains, though longer chains of up to ten conidia have infrequently been observed. Dendryphion is characterized by a definite, erect, closely branched conidiophore upon which chains of multiseptate smooth conidia develop, whereas Dendryphiella possesses a much more lax conidiophore, and usually three-septate, somewhat roughened conidia described as verruculose in D. interseminata by Ellis, Ellis & Ellis (1951)
Fungi in coastal soils. V. G. J. F. Pugh and J. Nicot
265
and' faiblement echinulee ' in D. arenaria by Nicot (1958). The formation of these conidia in short chains might raise some doubts about placing any of these species in Dendryphiella as the original description of the genus says that the spores are not formed in chains ('nicht kettenformig', Bubak & Ranojevic, in Ranojevic, 1914). However, in culture the type species does produce short chains of conidia.
····ca
·c ep -en
e
-
10/-,
Fig. 2. Dendryphiella arenaria. (Fig. I of Nicot, 1958.) a, Aspect de l'appareil conidien; b, spores mures ; c, detail des conidiophores; formation des spores; d, spores en voie de germination; e, detail des parois d'une spore vue en coupe optique;f, spores d'une culture sur milieu it 3,4% de NaC!. (a et dx 700; b, c,fx 1,100; e, schematique.)
Cercospora salina and Dendryphiella arenaria possess many features in common, ecologically, physiologically and morphologically. Both occur in coastal regions subjected to inundation by the sea, and both are able to grow well in media to which NaGl has been added. Maximum increase in colony diameter of the former at 25° G. occurred between 1 and 2 % NaGl; at 3'2 % it grew at the same rate as a colony without added salt, and at 10 % salt (the upper limit used) it still produced active growth. D. arenaria, as shown by Nicot (1958), attained the same colony diameter 17
Myc. 47
266
Transactions British Mycological Society
at 3'4 % NaCI as a control culture without added salt, and th e amount of gro wth gradually decreased up to 20 % salt (the maximum used ). On the saline medi a D. armaria appeared to produce smooth-walled conidia, many of which were 5-scptatc. Morphologically the conidiophores of both species arc very similar, as is the method of spore formation at pores and the production of conidia in short chains which may branch.
2
"
,
Fig. 3. Dendryphiellasalina. (Cncospora salina, Fig. 4 of Sutherland, 1916.) I , Cr eeping my celium with types of erect conidiophores ; 2, de veloping conidia ; 3, types of conidia; 4, germination of conidium showing immediate development of long , narrow type in salt water; 5, development of cell masses.
Consequently, these two species are regarded as being congeneric, and they have some features of both Dendryphion and Dendryphiella. Among the criteria to be evaluated in making a decision between these genera are the form of the conidiophore, the degree of septation of the conidia, and the texture of the conidial wall. The morphology of the diffuse conidiophore has been adopted as th e primary character, because the conidia of D. arenaria have be en shown to be very variable on media containing salt. Dendryphiella appears to be the more suitable genus for Cercospora salina, and this species is therefore transferred as D. salina (Sutherl and ) comb.nov. (basionym C. salina Sutherland in New Phytol. 15, p. 43, 1916) . The three species of Dendryphiella are easily distinguishable from each other. D . inierseminata has an erect conidiophore 210-300 It long, bearing mainly three-septate conidia 16-25 (21) x 6--B (7),U . (Ellis et al. 1951 ). In D. armaria the conidiophores may be 15-25# long, or much longer
Fungi in coastal soils. V. G.]. F. Pugh and]. Nicot
267
(80-go JL), bearing predominantly three-septate conidia 13-20 (15-17) x 4'5-6'5 (5"6) JL and also smaller r-septate conidia 10-15 (12- 14) x 3'55"5ft (Nicot, Ig58). The conidiophores of D. salina vary between I5-60ft, and generally resemble the shorter conidiophores of D. arenaria. Conidia are predominantly 3-5 septate, 20-45 x 6-g JL, with longer, 5-7 septate conidia, 45-70 x 6-9 JL (Pugh, 1962). We would like to thank Dr M. B. Ellis for most helpful discussions. REFERENCES
CHUPP, C. (1953). A monograph qfCercospora. Cornell University, Ithaca, N.Y. ELLIS, M. B., ELLIS, E. A. & ELLIS, J. P. (1951). British marsh and fen fungi. Trans. Brit. mycol, Soc. 34, 147-169. HUGHES, S. J. (1953). Conidiophores, conidia and classification. Ganad.]. Bot. 3 1 , 577659· JONES, E. B. G. (1962). Marine fungi. Trans. Brit. mycol. Soc. 45, 93-114. NICOT, J. (1958). Une moisissure arenicole du littoral atlantique: Dendryphiella arenaria sp.nov. Rev. Mycol., Paris, 23, 87-99. PUGH, G. J. F. (1962). Studies on fungi in coastal soils. 1. Cercospora salina Sutherland. Trans. Brit. mycol. Soc. 45, 255-260. RANOJEVIC, N. (1914). Dritter Beitrag zur Pilzflora Serbiens. Ann. mycol., Berl., 12, 393-421. SUTHERLAND, G. K. (1916). Marine Fungi Imperfecti. New Phytol. 15, 35-48. WILSON, 1. M. (1951). Notes on some marine fungi. Trans. Brit. mycol. Soc. 34, 540-543.
(Accepted for publication 18 November 1963)
17-2