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Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915

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Clypeostroma hemisphaericum (Berk.) Theiss. & Syd., Ann. Mycol. 13 609 (1915)
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915

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Endemic
Present
New Zealand
Political Region

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(Berk.) Theiss. & Syd.
Berk.
Theiss. & Syd.
1915
609
ICN
NZ holotype
species
Clypeostroma hemisphaericum

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hemisphaericum

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Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915

ITS, LSU, and mtSSU gene trees for Clypeostroma together with GenBank accessions selected from BLAST search results. The two Clypeostroma spp. appear to be congeneric. Johnston (NZJBot 40: 265-268, 2002) earlier noted that based on morphology they may represent different genera. The phylogenies from the three genes support their position in the Teratosphaeriaceae. ML-like trees generated using FastTree in Geneious. [PRJ, Oct 2018]

Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915

SPECIMEN EXAMINED: NEW ZEALAND: AUCKLAND ISLANDS: on Hebe odora (as Veronicaodora), K (M 85260) ex Herb. Berk. - Holotype ofDothidea hemisphaerica.
The type specimen comprises a few fragments of leaf, with 2 ascomata, one cut in half. Ascomata on lower surface of leaves, forming black, tar-spot-like symptoms, round in outline, 1.2-1.5 mm diam.,raised, hemispherical, up to 0.5 mm high, tapering suddenly toward the slightly inrolled margin. Surface black, slightly sculptured in appearance due to pseudothecial mounds. Outermost tissue of ascoma black, lined with globose to slightly cylindric pseudothecia about 80-100 µm diam., ascomatal tissue beneath pseudothecia very dark brown, base of ascoma has what appears to be a black lower wall. Ascomatal tissue releasing a bluish pigment in KOH. Ascospores 21.5-25 x 6.5-7.5 µm, cylindric, 1-septate, constricted slightly at the more or less central septum, upper cells slightly wider than lower, wall dark brown, smooth to finely punctate. Asci and paraphyses not seen.
DISCUSSIONAlthough the only material of Clypeostroma hemisphaericum available is fragmentary, this species is clearly distinct from C. spilomeum. They differ in macroscopic appearance of the ascomata, in ascomatal structure, and in ascospore size and colour.They are probably specialised toward different hosts. The differences in ascomatal structure suggest they belong in different genera. C. hemisphaericumhas a true stromatic ascoma with a distinct lower wall and uniformly dark (probably fungal) internal tissue, whereas the internal tissue of the raised ascoma of C. spilomeum comprises mostly host cells beneath a clypeus-like layer. Without additional material ofC. hemisphaericum, allowing examination of asci,hamathecial tissues, and ascomatal insertion, it is not possible to speculate on where this species may be better placed. C. spilomeum is the type species of the genusClypeostroma. While its asci are typical of the fissitunicate ascomycetes, where it belongs amongst these fungi is uncertain. The lack of hamathecial tissue suggests a relationship with the Dothideales sensu Barr (1987), but the immersed, globose, thinwalled pseudothecia aggregated beneath a common, subcuticular clypeus appears to fit no family within this taxon. Ascomatal structure is similar to some taxa within the Venturiaceae. For example,Sivanesan (1977) discussed a group of Venturia species with a clypeus above the more or less globose, thin-walled pseudothecia. Venturia, however,is characterised by the formation of filamentous pseudoparaphyses, and typically the ascomata develop on dead tissue as an overwintering phase in the life cycle. I retain C. spilomeum in Clypeostroma,but suggest no relationship for it amongst the bitunicate ascomycetes.
[Notes from Kew Type specimen, PRJ 2010] Big ascomata, as tall as they are wide. Photos from 2 packets on the type sheet, one with drawings, one without. The one with drawings accessioned as K(M) 85260, and is the collection I examined.

Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915

Die Phyllachora-artigen Stromata sind kreisförmig, scharf umrandet, glatt, halbglänzend, leicht gewölbt, etwa 1 mm im Durchmesser, schwarz; Oberfläche feinkörnig. Das Stroma erfült als Clypeus die Epidermis; die perithezienartigen Gehäuse liegen einzeln, aber ziemlich dicht ge-drängt unter der Epidermis, im oberen Teil mit dem Stroma verwachsen und dort auch unter sich stromatisch verbunden, im unteren Teil untereinander frei; Wand gut differenziert. Bei der Reife bricht die stromatische Deckschicht erst mit einer feinen Öffnung auf, welche nächtraglich durch weiteres Auseinanderweichen der Ränder sich stark vergroert. Paraphysen fehlen. Die Schläuche sind nur ganz kurz gestielt, am Grunde bauchig, nach oben sehr allmählich sich verengend und über den unteren sporen-führenden Teil weit ausgezogen. Sporen 2-3-reihig, länglich schmal zylindrisch, vierzellig, 30-34 x 6-7 µ, in jeder Zelle einen groen rundlichen Öltropfen führend, an den Enden nicht spitz, höchstens am oberen Ende etwas zugespitzt. Die Fruchtschicht ist noch jung, viele Sporen noch farblos, zweizellig oder noch einzellig, die vierzelligen schon tiefgelb oder bräunlich, bei der Reife zweifellos braun.
Auf Blättern von Veronica odora und elliptica, Auckland's Islands.
Das Blatt wird durch die Wirkung des Parasiten von 420 µ normaler Dicke hypertrophisch bis auf 750-800 µ aufgetrieben. Die Lokuli sind auf -½ des Blattquerschnittes beschränkt; sie messen durcbschnittlich 180-200 µ im Diameter oder sind wenig breiter als hoch. - Dothidea. hemisphaerica ist derselbe Pilz, aber junger und noch sehr unreif.
Clypeostroma unterscheidet sich von Homostegia im wesentlichen durch den Mangel der Paraphysen, von Telimena durch gefärbte Sporen und mangelnde Paraphysen.

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Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd.
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. (1915)
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. (1915)
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. (1915)
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. (1915)

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Clypeostroma hemisphaericum (Berk.) Theiss. & Syd. 1915
New Zealand
Auckland Islands

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1cb183aa-36b9-11d5-9548-00d0592d548c
scientific name
Names_Fungi
17 February 1999
5 June 2002
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