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ECHIDNODES AULOGRAPHOIDES (BOMM., ROUSS. &SACC.) ROBERTSON COMB.NOV., IN BRITAIN

By NOEL ROBERTSON, Botany School, University ofCambridge

(With 1 Text-figure)

In the spring of 1944 and again in 1945 fructifications of a fungus whichwas clearly a member of the Microthyriales (sensu C. G. Hansford) werecollected on the bark of living twigs of rhododendrons of the Ponticumseries, at Dawick, Peebleshire, Scotland. The fungus agrees closely withthe original description of Lembosia aulographoides Bomm., Rouss. & Sacco(Saccardo, 1891), but it also agrees closely with the original description ofMicrothyrium rhododendri (Grove, 1933). Through the courtesy of Dr W.Robyns I have been able to examine specimens in the Herbarium of theBrussels Botanic Garden from the Herbarium of E. Bommer and E.Rousseau. Two of the packets are designated 'Typus' by the Belgianauthorities and are labelled 'Tervueren, Juillet 1889, leg. M.R., E.B.'.It seems certain that these are in fact the type specimens on which Bommer,Rousseau and Saccardo erected Lembosia aulographoides. From the BrusselsHerbarium I have also been able to examine Rehm's exsiccatus 1067collected by Madame Destree. Dr C. J. Hickman has kindly looked inGrove's Herbarium at Birmingham but can find no specimen of or referenceto Microthyrium rhododendri Grove. There is, however, at Kew a specimen ofM. rhododendri Grove. This specimen is from the herbarium of the Rev.P. G. M. Rhodes but is labelled entirely in Grove's handwriting. Moreover,after the name is written nom. nov. ad interim, and the locality and date aregiven as Caerdeon, Mer, 19. iv. 33. The original description cites a speci­men collected in March 1933 from Caerdeon, and it is probable that theKew specimen is a later collection from the type locality, but from theannotation it appears that this specimen was considered in the erection ofthe new species and it is probably a paratype.

The measurements and characters of these specimens are given in Table 1.

No ascospores or asci could be found in Grove's specimen of M. rhododendriand his original description is inserted at the appropriate place.

Table 1

Character

External myceliumHyphopodiaThyriotheciaAsciAscospores (10 spores)

My specimen

PresentNone

200-345 x 148-228/-'24-44 x 21-321-'17-23 X 7-12/-,

Grove's specimenPresentNone

135-351 x 108-202/-,35-40 x 20-25 I-'20-24 x9-101-'

Bommer and Rousseautype of

Lembosia aulographoidesPresentNone

270-480 x 135-270/-,34-44 x 24-311-'17-21 X 6-101-'

There is no discrepancy between any of the measurements and thepublished dimensions. There is also a very close agreement between the

108 Transactions British Mycological Society

fungi examined, and there is no doubt that they fall within the same species.The presence of the external mycelium and the shape of the thyriotheciumexcludes the fungus from Microthynum. On microscopic examination byreflected light it is generally not possible to observe any mycelium associatedwith the thyriothecia. Theissen (1913) was unable to demonstrate anymycelium when he examined Rehm's exsiccatus no. 1067 of Lembosiaaulographoides, and for this reason he placed it in his new genus Lembosina ofwhich it was the type. I have examined the type specimen of Lembosiaaulographoides and Rehm's exsiccatus no. 1067 and in both, as well as inGrove's Microthyrium rhododendri and the fungus collected by me, have beenable to demonstrate a well-developed ground mycelium , using the celluloseacetate stripping method.

According to Theissen & Sydow (1917) the fungus would fall in thegenera Lembosia or Echidnodes according to the presence or absence ofhyphopodia. There are certainly no lateral hyphopodia present, and theoccasional swellings on the hyphae are not intercalary hyphopodia (Cirsosiatransversalis, Herb. I.M.I. 13522, which has true intercalary hyphopodia,examined for comparison). Moreover, Mr M. B. Ellis of the Common­wealth Mycological Institute demonstrated the presence of a very fineinternal mycelium under the cuticle and in the epidermal cells (a feature ofEchidnodes) in one of my collections (R. 18, Herb. I.M.I. 34762). Theissen& Sydow (1917) and Stevens & Ryan (1939) make two genera Echidnodesand Echidnodella separated on the character of the presence or absence ofparaphyses. Hansford (1946) maintains that the presence or absence ofparaphyses is not a reliable character. In my own collections paraphysesare certainly present in young th yriothecia, but in older thyriothecia thesubstance surrounding the asci is a structureless mucus. Arnaud (1918)makes two genera Balansina and M aurodothella which approach close toEchidnodes and which Stevens & R yan treat as synonymous genera. I havenot had an opportunity of examining the type species of these genera andcannot say how the species under discussion relates to them. It certainlyagrees with Theissen & Sydow's original definition of Echidnodes.

My collection is identical with the type specimen of Lembosia aulogra­phoides Bomm., Rouss. & Sacco and with the specimen of Microthyriumrhododendri Grove in the Herbarium, Kew, and all three are correctlyreferred to the genus Echidnodes of Theissen & Sydow (1917) as follows:

Echidnodes aulographiodes (Bomm., Rouss. & Sacc.) comb.nov.

Syn. Lembosia aulographoides Bomrn. , Rouss. & Sacc., Saccardo, Sylloge fungorum, 9,1107 (18gl ) and Hedwigia, 31,3°4 (18g2).

Lembosina aulographoides (Bomm. , Rouss. & Sacc.), Theissen, Ann. mycol., Berl., 11,437(1913).

T ype material: 'In ramulis tenellis emortuis Rhododendri pontici, Ter­vueren Belgii.'

This species was treated as Microthyrium rhododendri by Grove (J. Bot.,Lond.,71, 287 (1933)) . He erected a type for M. rhododendri on Britishmaterial of his own collecting.

Echidnodes aulographoides. Noel Robertson 109

Type material: ' In ramulis emortuis v. semimortuis vetustissimorumRhododendrorum cultorum, Caerdeon prope Barmouth, Mer., Mart., 1933.'

The fungus found by me occurs on the living twigs of rhododendrons ofthe Ponticum series. In these species the cortex is not cut off as bark untilthe second or third year. It was on such newly formed bark in the earlyspring that the ripe fructifications were found. In the areas on which thefungu s occurred the bark took on a grey colour, distinct from the reddishcolour of normal bark. The collections of Grove, Destree, and Bommer andRousseau were on dead twigs of rhododendrons. In the herbarium speci­mens some of the twigs are of considerable age and on these the fructificationsand external mycelium are poor and the latter difficult to demonstrate.The best specimens containing asci and ascospores are found on the youngtwigs. I do not consider that the fungus I collected was either saprophyticor seriously pathogenic. In one instance fructifications of the fungus werefound on a dead area of a leaf of rhododendron. Although Chinese rhodo­dendrons were common in the same area none was infected with thisfungus.

The fructifications occur on an external brown mycelium composed ofsmooth-walled anastomosing hyphae 2-3(4){£ in diameter. They areth yriothecia (see fig. I), black, dimidiate and elongated 20()--,345 x 148-

Fig. 1. Echidnodes aulographoides, thyriothecium in transverse section.

228{£; the cover is made up of radiating hyphae, it is dark and opaque inthe centre becoming translucent towards the edges. The thyriothecia openby an irregular longitudinal slit which occasionally bifurcates. The asci,which are arranged in one basal layer, are globose and slightly thickenedat the apex, 24-44 x 21-32{£, containing eight ascospores which are bi­cellular, constricted at the septum, with the lower cell slightly narrowerthan the upper one, and measuring 17-23 x 7-12{£. The ascospores arehyaline at first, becoming pale brown with verruculose walls. The hyalinespores are much the more numerous in all the preparations examined butthe brown spores also belong to the fungus, for in a few preparations theyhave been found within an ascus. The paraphyses are demonstrable in a fewpreparations.

Collections examined

Herb. R.B.G. Kew; Brit. Col.: "Microthyrium rhododendri; nov.nom, adinterim, on branches of Rhododendron, Caerdeon, Mer. 19. iv, 33.'(scripsit Grove). Herbarium of the Rev. P. G. M. Rhodes, Beq. March 1935.

no Transactions British Mycological Society

Herb. Hort. botan. Brux: 'Lembosia aulographoides Bomm., Rouss. & SaccoSur de jeunes rameaux morts de Rhododendron ponticum. Pare de (? Verom) ,Tervueren, Juillet 188g. Leg. M.R., E.B.' Ex Herb. E. Bommer andM. Rousseau.

Herb. Hort. botan. Brux. Rehm's Ascomycetes no. 1067. 'Lembosiaaulographoides Bomm., Rouss. & Sacco On Rhododendron ponticum aesten.Jardin aux environs de la Haye (Nederland), 18gl.' Madame Destree.

On Rhododendron twigs: Dawick, Peebleshire, Scotland, Ig. ii. 44, leg.Noel Robertson, no. 17.

On Rhododendron twigs: Dawick, Peebleshire, Scotland, iv. Ig45, leg.Noel Robertson, no. 18. (I.M.I. 34762.)

The occurrence of this member of the Microthyriales in Britain is of interestin itself, but it is also of practical importance to those who teach systematicmycology and who may not have access to herbarium material of these,usually tropical, fungi.

I am indebted to Dr W. Robyns, Director of the BrusselsBotanic Garden,The Director, the Royal Botanic Garden, Kew, and Dr S. P. Wiltshire,Director, Commonwealth Mycological Institute, for facilities for theexamination of specimens; to Miss E. M. Wakefield, Dr Malcolm Wilsonand Messrs E. W. Mason, S. H. Hughes and M. B. Ellis for helpfuldiscussion.

REFERENCES

ARNAUD, G. (1918). Les Asterinees, 1. Ann. de He. Agric. Montpellier, 16, 1-288.GROVE, W. B. (1933). New or noteworthy fungi. XIII. ]. Bot., Lond., 71, 287.!lANSFORD, C. G. (1946). The foliicolous ascomycetes, their parasites and associated fungi.

Imp. Mycol. Inst. Mycological Papers, 15, 1-240.SACCARDO, P. A. (1891). Syllogefungorum, 9, 1107.

STEVENS, F. L. & RYAN MARy H. (1939). The Microthyriaceae. Illinois biol. Monogr. 17,no. 2.

THEISSEN, F. (1913). Lembosia-Studien. Ann. mycol., Berl., 11,437.THEISSEN, F. & SYDOW, H. (1917). Synoptische Tafeln, Ann. mycol., Berl., 15,389.

(Accepted for publication 31 May 1949)