- Email: [email protected]
Hyphomycete spores from mountain torrents
[ 453 ] Trans. Brit. mycol. Soc. 48 (3), 453-45 8 (19 65) Printed in Great Britain
HYPHOMYCETE SPORES FROM MOUNTAIN TORRENTS By C. T. INGOLD
Birkbeck College, University of London (With 4 Text-figures) A number of branched spores, presumably conidia of aquatic hyphomycetes, are illustrated from foam samples from the Linn of Dee, Scotland, and Glenariff, Northern Ireland. It is considered that one spore type belongs to the genus Ingoldia and another to Triposporina. Culicidospora aquatica R. H. Petersen is reported from both localities. The fungi from which these spores are derived may be growing on submerged wood.
For more than 20 years I have been interested in the aquatic hyphomycetes which grow mainly on decaying leaves of dicotyledonous trees and shrubs in the beds of streams. Since my first paper on this subject (Ingold, 1942) the literature has grown considerably and this is fully cited in two recent taxonomic summaries of these fungi by Petersen (1962, 1963 a, b) and Nilsson (1964). Aquatic hyphomycetes are abundant in well-aerated streams and can almost invariably be found on submerged leaves which have become brown and are beginning to develop into leafskeletons, particularly on the petioles and main veins. If collected leaves are well washed and left in shallow dishes of water for a day in the laboratory, and then examined directly under the low power of the microscope, the conidiophores projecting into the water can easily be seen. Usually several species, readily identifiable under this low magnification, can be found on a single leaf. These fungi reach their richest development in late November or early December when the leaves of deciduous broad-leaved trees and shrubs are so abundant in streams, but can be found at all times of the year. Although the pattern of development is so important in the taxonomy of these fungi, most species can be identified with reasonable certainty from the liberated hyaline spores. In a stream there are natural spore-traps in the form of scum or foam. Although the spores are slightly denser than water, those which happen to be brought to the surface by turbulence are easily trapped by a layer of scum such as frequently accumulates upstream of a temporary barrier of twigs in a small stream. Cakes of foam formed in torrents below waterfalls, especially after heavy rain, are even more efficient as spore-traps. If foam is patiently collected and allowed to break down to water, the resulting aqueous suspension from a torrent coursing through a wooded region is amazingly rich in spores of aquatic hyphomycetes. From such a suspension a picture is rapidly obtained of the fungus flora of the stream. If, however, it is wished to make a thorough 29
~yc.
48
Transactions British Mycological Society
454
study of these fungi, and particularly if pure cultures are desired, examination of decaying leaves is the proper course. During the past two decades I have examined samples of decaying leaves from streams in many parts of Britain and the same fungi, over thirty species, have been found repeatedly. I had gained the impression that few new forms remained undescribed. However, as a result of recent examination of the spores in foam from two torrents, it is clear that a considerable range of undescribed species awaits study. The first torrent was in Scotland, the Linn of Dee, several miles upstream from Braemar, visited during the post-Botanical Congress excursion
Fig.
I.
A, ? Ingoldia sp. : 1-9, spores from Linn of Dee; 10-12, spores from Glenariff; B, Triposporina sp.: spores from Linn of Dee.
of mycologists to Aberdeen in mid-August 1964. After many hours of continuous rain the Dee was in spate and the raging torrent was casting cakes of foam along its banks. A sample of this foam was collected. The second was in the Glens of Antrim at Glenariff in Northern Ireland, visited in September 1964 during the Society's autumn foray. Again the river, cascading down a steep and narrow glen with numerous waterfalls, was in spate after a morning of very heavy rain, and large cakes of foam were eddying in the pools below the falls. Again a sample of foam was collected. In both samples there were many spores of known fungi, but others were not assignable to described species and of these some were completely new to me. Further, of the new types, a number were common to the two torrents in spite of their considerable geographical separation. The type of spore shown in Fig. I A was abundant in the Dee sample but relatively rare in that from Glenariff. Hundreds of spores have been examined. I have never seen it before, but it agrees with one figured by Tubaki (1960) from Japan. Further, it seems quite clear that these spores belong to an undescribed species of Ingoldia of which two species have so
Hyphomycete spores. C. T. Ingold
455
far been erected: the type, 1. craginiformis R. H. Petersen, and 1. tricapillata Ingold (1964). In all three, the spore consists of a main septate axis, from which arises a first-order lateral (or sometimes two), and this (or the lower one if two are present) branches near its base to produce a second-order lateral. The main axis and the laterals taper to rather fine points and the insertion of each lateral is extremely narrow and difficult to demonstrate, the laterals often appearing completely separate. In 1. craginiformis the spore normally has two first-order laterals, but in I. tricapillata, and in the spores from the torrents, the upper lateral only rarely occurs. At first sight these spores
A
c SOil
Fig. 2. A, ? Triposporina sp.: top six spores from Linn of Dee, bottom spore from Glenariff; B, spores of unknown fungus from Linn of Dee; C, spores of unknown fungus from Glenariff.
with their relatively straight axes look very different from those of 1. craginiformis with their remarkably curved axes, but closer examination reveals the underlying similarity. It is of interest to note that a few spores of 1. craginiformis occurred in the two scum samples studied, making new records of this species for both Scotland and Ireland. The spores illustrated in Fig. 1B were common in the Dee sample, but were not found at Glenariff. They seem to belong to T riposporina sp. and, indeed, are very similar to those of T. quadridens Drechsl., a predaceous species described in 1961. The spore consists of a stalk portion which dichotomizes twice to give a 5-radiate spore. Commonly two of the arms overlap. Fig. 2A illustrates a type of spore found rarely in the Dee sample but fairly commonly in that from Glenariff. I have occasionally seen spores, at least of the same generic form, in scum and foam samples from various parts of the world, including Britain (Ingold, 1942), Nigeria (Ingold, 1959)Jamaica (Hudson & Ingold, 1960) and New Zealand (unpublished).
Transactions British Mycological Society This type of spore has already been compared (Ingold & Cox, 1957) with spores of Campylospora, but a fairer comparison would be with Triposporina. This can be seen on comparing Figs. I Band 2 A. In the spores from the Dee and Glenariff, however, septa could not be demonstrated with certainty. The curious little fan-shaped spores shown in Fig. 2B were frequent in the Dee sample, but rare in the Glenariff foam. Each consists of a closely branched filamentous system of a pinnate nature usually confined to a
S
6
4
II I
SOp Fig. 3. A, spores of unknown fungus from Glenariff; B. spores of unknown fungus: 1-5 from Glenariff; 6 from Linn of Dee.
single plane. There is a main axis of 4-5 cells beset with short, branched laterals, the individual cells being very small. What is presumably the basal attachment cell is clearly defined. It is difficult to suggest a possible genus for these spores, though there is some resemblance to Speiropsis. Another, possibly co-generic, type of spore, with short unbranched laterals and with very much larger individual cells, occurred as a rare member of the Glenariff spora (Fig. 2 C). Fig. SA shows a kind of spore common in the Glcnariff scum, but relatively rare in the Dee sample. Generically it agrees fairly well with a type illustrated from Spain (Nilsson, 1960). There is a straight main axis, close to the base of which an opposite pair (or more rarely a three-member whorl) of primary laterals arises. Occasionally, an additional lateral develops at a higher level. Some or all of the primary laterals branch again close to the base to give secondary laterals, and some of these may branch again in the same manner. This kind of spore would seem to fit into the
Hyphomycete spores. C. T. Ingold
457
pattern characteristic of Triscelophorus and Dendrospora. How these two genera may possibly merg e into one another has already been discussed (I ngold, 1960). Foam samples from both localities contained many spores of the type shown in Fig. 3 B. The spore consisted of a narrow straight stalk, either aseptate or obscurely septate, terminated by a tuft of 4-8 long, but somewhat fusiform , bran ches, clearl y septate. In both th e Linn of Dee and Glenariff samples spores of Culicidospora aquatica Petersen (1960) wer e common (Fig. 4A), constituting a new record for th e British Isles.
A
SO p Fig. 4- A, Culicidospora aquatica, spores from Glenariff; B, from Linn of Dee ; 3 an d 4, un known spores from Glenariff.
I and 2 , unknown spores 2 , dra wn to smaller scale.
Fig. 4 B, r , illustrates a very striking spore from the Dee . There is a short stalk part, from the ap ex of which there is a V-shaped development. Two similar secondary V-shaped outgrowths occur on either side of the stalk near th e base of the primary V-branch. The whol e is highly and obviously septat e. This seems to be totally different from any other kind of branched spore previously reported. Large spores of the typ e shown in Fig. 4B, 2, wer e fairly common in the Dee sample. They would seem to belong to T riscelophorus and may possibly be identified as T. magnijicus Petersen (1962). The other two kinds ofspore shown in Fig. 4B (3 and 4) wer e common in both samples and, indeed, in my experience are almost always present in scum and foam samples. Nevertheless, only the spores ar e known and the fungi concern ed remain undescrib ed. The larger typ e with its cells stuffed with glycogen is of a pearly appearance. There ar e either four or , rather more commonly, five arms and th ese, unlike th e spore figured, usually do not lie in a single plane. The clearly septate arms ar ise from a small spherical region with a short curved stalk no doub t concern ed wit h att achment to the conidiophore. This spore may well belong to a species of Tetranacrium Hudson & Sutton ( 1964). In spit e of their abundan ce in foam and scum,
Transactions British Mycological Society the two fungi whose spores are figured have never been seen on submerged leaves. This rather suggests that there is another type of substratum providing a supply of these spores and the others considered in this paper. A strong possibility would seem to be submerged wood and in this connexion it is of interest to note that Jones & Oliver (1964) have recorded a number of aquatic hyphomycetes growing on submerged wood-blocks. REFERENCES
DRECHSLER, C. (1961). Some clampless hyphomycetes predacious on nematodes and rhizopods. Sydowia, 15, 17-22. HUDSON, H.J. & INGOLD, C. T. (1960). Aquatic hyphomycetes from Jamaica. Trans. Br. mycol. Soc. 43, 469-478. HUDSON, H.J. & SUTTON, B. C. (1964). Trisulcosporium and Tetranacrium, two new genera of Fungi Imperfecti. Trans. Br. mycol. Soc. 47, 197-203. INGOLD, C. T. (1942). Aquatic hyphomycetes of decaying alder leaves. Trans. Br. mycol. Soc. 25, 339-417. INGOLD, C. T. (1959). Aquatic spora of Omo Forest, Nigeria. Trans. Br. mycol. Soc. 42, 479-485. INGOLD, C. T. (1960). Aquatic hyphomycetes from Canada. Can.]. Bot. 38, 803-806. INGOLD, C. T. (1964). A new species of Ingoldia from Britain. Trans. Br. mycol. Soc. 47, 103-107. INGOLD, C. T. & Cox, V. J. (1957). On Tripospermum and Campylospora. Trans. Br. mycol. Soc. 40, 317-321. JONES, E. B. G. & OLIVER, A. C. (1964). Occurrence of aquatic hyphomycetes on wood submerged in fresh and brackish water. Trans. Br. mycol, Soc. 47, 45-48. NILLSON, S. (1960). Aquatic hyphomycetes from northern Spain. Svensk bot. Tidskr.54, 530-53 2. NILLSON, S. (1964). Freshwater hyphomycetes. Symb. bot. upsal. 18, 1-130. PETERSEN, R. H. (1960). Culicidospora, a new genus of aquatic, aleuriosporous hyphomycetes. Bull. Torrey bot. Club, 87, 342-347. PETERSEN, R. H. (1962). Aquatic hyphomycetes from North America. I. Aleuriosporae (Part I), and key to the genera. Mycologia, 54, 117-15 I. PETERSEN, R. H. (1963a). Aquatic hyphomycetes from North America. II. Aleuriosporae (Part 2), and Blastosporae. Mycologia, 55, 18-29. PETERSEN, R. H. (1963b). Aquatic hyphomycetes from North America. III. Phialosporae and miscellaneous species. Mycologia, 55, 570-581. TUBAKI, K. (1960). On the Japanese aquatic hyphomycetes. Scum and foam group, referring to the preliminary survey of the snow group. Nagaoa, 17-28.
(Accepted for publication 15 December 1964)
HYPHOMYCETE SPORES FROM MOUNTAIN TORRENTS By C. T. INGOLD
Birkbeck College, University of London (With 4 Text-figures) A number of branched spores, presumably conidia of aquatic hyphomycetes, are illustrated from foam samples from the Linn of Dee, Scotland, and Glenariff, Northern Ireland. It is considered that one spore type belongs to the genus Ingoldia and another to Triposporina. Culicidospora aquatica R. H. Petersen is reported from both localities. The fungi from which these spores are derived may be growing on submerged wood.
For more than 20 years I have been interested in the aquatic hyphomycetes which grow mainly on decaying leaves of dicotyledonous trees and shrubs in the beds of streams. Since my first paper on this subject (Ingold, 1942) the literature has grown considerably and this is fully cited in two recent taxonomic summaries of these fungi by Petersen (1962, 1963 a, b) and Nilsson (1964). Aquatic hyphomycetes are abundant in well-aerated streams and can almost invariably be found on submerged leaves which have become brown and are beginning to develop into leafskeletons, particularly on the petioles and main veins. If collected leaves are well washed and left in shallow dishes of water for a day in the laboratory, and then examined directly under the low power of the microscope, the conidiophores projecting into the water can easily be seen. Usually several species, readily identifiable under this low magnification, can be found on a single leaf. These fungi reach their richest development in late November or early December when the leaves of deciduous broad-leaved trees and shrubs are so abundant in streams, but can be found at all times of the year. Although the pattern of development is so important in the taxonomy of these fungi, most species can be identified with reasonable certainty from the liberated hyaline spores. In a stream there are natural spore-traps in the form of scum or foam. Although the spores are slightly denser than water, those which happen to be brought to the surface by turbulence are easily trapped by a layer of scum such as frequently accumulates upstream of a temporary barrier of twigs in a small stream. Cakes of foam formed in torrents below waterfalls, especially after heavy rain, are even more efficient as spore-traps. If foam is patiently collected and allowed to break down to water, the resulting aqueous suspension from a torrent coursing through a wooded region is amazingly rich in spores of aquatic hyphomycetes. From such a suspension a picture is rapidly obtained of the fungus flora of the stream. If, however, it is wished to make a thorough 29
~yc.
48
Transactions British Mycological Society
454
study of these fungi, and particularly if pure cultures are desired, examination of decaying leaves is the proper course. During the past two decades I have examined samples of decaying leaves from streams in many parts of Britain and the same fungi, over thirty species, have been found repeatedly. I had gained the impression that few new forms remained undescribed. However, as a result of recent examination of the spores in foam from two torrents, it is clear that a considerable range of undescribed species awaits study. The first torrent was in Scotland, the Linn of Dee, several miles upstream from Braemar, visited during the post-Botanical Congress excursion
Fig.
I.
A, ? Ingoldia sp. : 1-9, spores from Linn of Dee; 10-12, spores from Glenariff; B, Triposporina sp.: spores from Linn of Dee.
of mycologists to Aberdeen in mid-August 1964. After many hours of continuous rain the Dee was in spate and the raging torrent was casting cakes of foam along its banks. A sample of this foam was collected. The second was in the Glens of Antrim at Glenariff in Northern Ireland, visited in September 1964 during the Society's autumn foray. Again the river, cascading down a steep and narrow glen with numerous waterfalls, was in spate after a morning of very heavy rain, and large cakes of foam were eddying in the pools below the falls. Again a sample of foam was collected. In both samples there were many spores of known fungi, but others were not assignable to described species and of these some were completely new to me. Further, of the new types, a number were common to the two torrents in spite of their considerable geographical separation. The type of spore shown in Fig. I A was abundant in the Dee sample but relatively rare in that from Glenariff. Hundreds of spores have been examined. I have never seen it before, but it agrees with one figured by Tubaki (1960) from Japan. Further, it seems quite clear that these spores belong to an undescribed species of Ingoldia of which two species have so
Hyphomycete spores. C. T. Ingold
455
far been erected: the type, 1. craginiformis R. H. Petersen, and 1. tricapillata Ingold (1964). In all three, the spore consists of a main septate axis, from which arises a first-order lateral (or sometimes two), and this (or the lower one if two are present) branches near its base to produce a second-order lateral. The main axis and the laterals taper to rather fine points and the insertion of each lateral is extremely narrow and difficult to demonstrate, the laterals often appearing completely separate. In 1. craginiformis the spore normally has two first-order laterals, but in I. tricapillata, and in the spores from the torrents, the upper lateral only rarely occurs. At first sight these spores
A
c SOil
Fig. 2. A, ? Triposporina sp.: top six spores from Linn of Dee, bottom spore from Glenariff; B, spores of unknown fungus from Linn of Dee; C, spores of unknown fungus from Glenariff.
with their relatively straight axes look very different from those of 1. craginiformis with their remarkably curved axes, but closer examination reveals the underlying similarity. It is of interest to note that a few spores of 1. craginiformis occurred in the two scum samples studied, making new records of this species for both Scotland and Ireland. The spores illustrated in Fig. 1B were common in the Dee sample, but were not found at Glenariff. They seem to belong to T riposporina sp. and, indeed, are very similar to those of T. quadridens Drechsl., a predaceous species described in 1961. The spore consists of a stalk portion which dichotomizes twice to give a 5-radiate spore. Commonly two of the arms overlap. Fig. 2A illustrates a type of spore found rarely in the Dee sample but fairly commonly in that from Glenariff. I have occasionally seen spores, at least of the same generic form, in scum and foam samples from various parts of the world, including Britain (Ingold, 1942), Nigeria (Ingold, 1959)Jamaica (Hudson & Ingold, 1960) and New Zealand (unpublished).
Transactions British Mycological Society This type of spore has already been compared (Ingold & Cox, 1957) with spores of Campylospora, but a fairer comparison would be with Triposporina. This can be seen on comparing Figs. I Band 2 A. In the spores from the Dee and Glenariff, however, septa could not be demonstrated with certainty. The curious little fan-shaped spores shown in Fig. 2B were frequent in the Dee sample, but rare in the Glenariff foam. Each consists of a closely branched filamentous system of a pinnate nature usually confined to a
S
6
4
II I
SOp Fig. 3. A, spores of unknown fungus from Glenariff; B. spores of unknown fungus: 1-5 from Glenariff; 6 from Linn of Dee.
single plane. There is a main axis of 4-5 cells beset with short, branched laterals, the individual cells being very small. What is presumably the basal attachment cell is clearly defined. It is difficult to suggest a possible genus for these spores, though there is some resemblance to Speiropsis. Another, possibly co-generic, type of spore, with short unbranched laterals and with very much larger individual cells, occurred as a rare member of the Glenariff spora (Fig. 2 C). Fig. SA shows a kind of spore common in the Glcnariff scum, but relatively rare in the Dee sample. Generically it agrees fairly well with a type illustrated from Spain (Nilsson, 1960). There is a straight main axis, close to the base of which an opposite pair (or more rarely a three-member whorl) of primary laterals arises. Occasionally, an additional lateral develops at a higher level. Some or all of the primary laterals branch again close to the base to give secondary laterals, and some of these may branch again in the same manner. This kind of spore would seem to fit into the
Hyphomycete spores. C. T. Ingold
457
pattern characteristic of Triscelophorus and Dendrospora. How these two genera may possibly merg e into one another has already been discussed (I ngold, 1960). Foam samples from both localities contained many spores of the type shown in Fig. 3 B. The spore consisted of a narrow straight stalk, either aseptate or obscurely septate, terminated by a tuft of 4-8 long, but somewhat fusiform , bran ches, clearl y septate. In both th e Linn of Dee and Glenariff samples spores of Culicidospora aquatica Petersen (1960) wer e common (Fig. 4A), constituting a new record for th e British Isles.
A
SO p Fig. 4- A, Culicidospora aquatica, spores from Glenariff; B, from Linn of Dee ; 3 an d 4, un known spores from Glenariff.
I and 2 , unknown spores 2 , dra wn to smaller scale.
Fig. 4 B, r , illustrates a very striking spore from the Dee . There is a short stalk part, from the ap ex of which there is a V-shaped development. Two similar secondary V-shaped outgrowths occur on either side of the stalk near th e base of the primary V-branch. The whol e is highly and obviously septat e. This seems to be totally different from any other kind of branched spore previously reported. Large spores of the typ e shown in Fig. 4B, 2, wer e fairly common in the Dee sample. They would seem to belong to T riscelophorus and may possibly be identified as T. magnijicus Petersen (1962). The other two kinds ofspore shown in Fig. 4B (3 and 4) wer e common in both samples and, indeed, in my experience are almost always present in scum and foam samples. Nevertheless, only the spores ar e known and the fungi concern ed remain undescrib ed. The larger typ e with its cells stuffed with glycogen is of a pearly appearance. There ar e either four or , rather more commonly, five arms and th ese, unlike th e spore figured, usually do not lie in a single plane. The clearly septate arms ar ise from a small spherical region with a short curved stalk no doub t concern ed wit h att achment to the conidiophore. This spore may well belong to a species of Tetranacrium Hudson & Sutton ( 1964). In spit e of their abundan ce in foam and scum,
Transactions British Mycological Society the two fungi whose spores are figured have never been seen on submerged leaves. This rather suggests that there is another type of substratum providing a supply of these spores and the others considered in this paper. A strong possibility would seem to be submerged wood and in this connexion it is of interest to note that Jones & Oliver (1964) have recorded a number of aquatic hyphomycetes growing on submerged wood-blocks. REFERENCES
DRECHSLER, C. (1961). Some clampless hyphomycetes predacious on nematodes and rhizopods. Sydowia, 15, 17-22. HUDSON, H.J. & INGOLD, C. T. (1960). Aquatic hyphomycetes from Jamaica. Trans. Br. mycol. Soc. 43, 469-478. HUDSON, H.J. & SUTTON, B. C. (1964). Trisulcosporium and Tetranacrium, two new genera of Fungi Imperfecti. Trans. Br. mycol. Soc. 47, 197-203. INGOLD, C. T. (1942). Aquatic hyphomycetes of decaying alder leaves. Trans. Br. mycol. Soc. 25, 339-417. INGOLD, C. T. (1959). Aquatic spora of Omo Forest, Nigeria. Trans. Br. mycol. Soc. 42, 479-485. INGOLD, C. T. (1960). Aquatic hyphomycetes from Canada. Can.]. Bot. 38, 803-806. INGOLD, C. T. (1964). A new species of Ingoldia from Britain. Trans. Br. mycol. Soc. 47, 103-107. INGOLD, C. T. & Cox, V. J. (1957). On Tripospermum and Campylospora. Trans. Br. mycol. Soc. 40, 317-321. JONES, E. B. G. & OLIVER, A. C. (1964). Occurrence of aquatic hyphomycetes on wood submerged in fresh and brackish water. Trans. Br. mycol, Soc. 47, 45-48. NILLSON, S. (1960). Aquatic hyphomycetes from northern Spain. Svensk bot. Tidskr.54, 530-53 2. NILLSON, S. (1964). Freshwater hyphomycetes. Symb. bot. upsal. 18, 1-130. PETERSEN, R. H. (1960). Culicidospora, a new genus of aquatic, aleuriosporous hyphomycetes. Bull. Torrey bot. Club, 87, 342-347. PETERSEN, R. H. (1962). Aquatic hyphomycetes from North America. I. Aleuriosporae (Part I), and key to the genera. Mycologia, 54, 117-15 I. PETERSEN, R. H. (1963a). Aquatic hyphomycetes from North America. II. Aleuriosporae (Part 2), and Blastosporae. Mycologia, 55, 18-29. PETERSEN, R. H. (1963b). Aquatic hyphomycetes from North America. III. Phialosporae and miscellaneous species. Mycologia, 55, 570-581. TUBAKI, K. (1960). On the Japanese aquatic hyphomycetes. Scum and foam group, referring to the preliminary survey of the snow group. Nagaoa, 17-28.
(Accepted for publication 15 December 1964)