RHYTISMA Fr. Rhytismataceae. 5 Ukrainian species on Acer, Andromeda and Salix.

1	on Acer	2
	not on Acer	3
2(1)	ascomata linked by conspicuous black stoma	Rhytisma acerinum
	ascomata not linked by conspicuous black stoma	Rhytisma punctatum
3(1)	on Andromeda	Rhytisma andromedae
	on Salix	4
4(3)	stroma circular, containing single ascoma	Rhytisma umbonatum
	stoma variously shaped, often containing more than one ascoma	Rhytisma salicinum

Rhytisma acerinum (Pers.) Fr. [click here for picture]. Status. Native; 159 records since 31 August 1895; very widespread and often abundant throughout Ukraine, almost everywhere Acer occurs. Months. March, April, May, June, July, August, September, October. Regions. Cherkasy, Chernihiv, Chernivtsi, Crimea, Donetsk, Ivano-Frankivsk, Kherson, Khmelnytskyi, Kiev, Kirovohrad, Poltava, Ternopil, Vinnytsia, Zakarpatska, Zaporyzhzhia. Habitat. On leaves of Acer campestre, Acer platanoides, Acer pseudoplatanus, Acer pseudoplatanus var. purpurascens, Acer stevenii, Acer tataricum and Acer sp.; probably most common on Acer pseudoplatanus; colonizing living leaves, causing the typical 'tarspots', but apparently never killing the tree. Notes. The conidial state is usually produced before leaf fall; the teleomorph appears in the litter the following spring; associated with various other fungi, including Dasyscypha rhytismatis, Discosia artocreas, Lachnum sp., Pyrenopeziza petiolaris, Sawadaia bicornis, Sawadaia tulasnei. Worldwide. Widespread and abundant on various species of Acer throughout Europe, North America, north Africa, and western Asia. References. Cannon & Minter (1984a) [description]; Garbowski (1923) [Ukrainian records]; Kharkevich (1959) [Ukrainian records]; Minter & Dudka (1996) [Ukrainian records]; Morochovskii, Zerova, Lavitskaya & Smitskaya (1969) [Ukrainian records].

Rhytisma andromedae (Pers.) Fr. [click here for picture]. Status. Native; 4 records since 4 September 1988; local and probably rather rare. Months. September. Regions. Volynska. Habitat. On leaves of Andromea polifolia; the fungus colonizes living leaves, causing typical 'tarspots', but apparently never killing the plant; probably always fruiting within 12 months of leaf death. Notes. This fungus is the only species of Rhytisma on Andromeda, and is easily recognized by the conspicuous black stromata on the leaves. Worldwide. On Andromeda and, far less frequently, other similar members of the Ericaceae; widespread but infrequently recorded in northern, western and central Europe and North America. References. Minter (1997d) [description]; Minter & Dudka (1996) [Ukrainian records]; Morochovskii, Zerova, Lavitskaya & Smitskaya (1969) [Ukrainian records].

Rhytisma punctatum (Pers.) Fr. Status. Native; 37 records since 5 August 1899. Months. April, June, August, September, October. Regions. Cherkasy, Crimea, Donetsk, Kiev, Poltava. Habitat. Acer campestre, Acer platanoides, Acer tataricum, Acer sp.; on living and, later, dead fallen leaves. Notes. The stroma of this species is much less extensive than that of Rhytisma acerinum, and individual ascomata are smaller, more regular in shape and tend to coalesce less frequently; in Rhytisma acerinum, the black stroma has formed large 'tarspots', usually before the leaf has fallen, and certainly before ascomata contain ascospores; in Rhytisma punctatum, ascomata and not united by a black stroma even when ascospores are present; Rhytisma punctatum is associated with other fungi, including Sawadaia tulasnei, and may occur on the same leaves as Rhytisma acerinum; probably always fruiting within 12 months of leaf death. Worldwide. On various species of Acer, widespread and locally not rare in Europe, North America and Asia, with altitude records up to 3000 m. References. Kharkevich (1959) [Ukrainian records]; Minter & Dudka (1996) [Ukrainian records]; Morochovskii, Zerova, Lavitskaya & Smitskaya (1969) [Ukrainian records].

Rhytisma salicinum (Pers.) Fr. [click here for picture]. Status. Native; 26 records since September 1909; widespread and locally not rare. Months. June, July, September, October, November. Regions. Cherkasy, Chernihiv, Crimea, Donetsk, Kiev, Lviv, Poltava, Zakarpatska. Habitat. On living and, later, dead leaves of Salix cinerea, Salix purpurea, Salix silesiaca and Salix sp. Notes. The fungus colonizes living leaves, causing typical 'tarspots', but apparently never killing the plant; probably always fruiting within 12 months of leaf death; Rhytisma salicinum and Rhytisma umbonatum, sometimes regarded as the same species, may be distinguished because Rhytisma umbonatum produces circular stromata, often simultaneously on both sides of the leaf, each with a circular ascoma, whereas stromata of Rhytisma salicinum are usually larger, more irregular in shape, and often contain several more or less coalescing ascomata. Worldwide. Widespread and locally abundant on leaves of many species of Salix in Europe and North America, with additional, probably native records from Africa and Asia. References. Garbowski (1923) [Ukrainian records]; Kharkevich (1959) [Ukrainian records]; Minter & Dudka (1996) [Ukrainian records]; Morochovskii, Zerova, Lavitskaya & Smitskaya (1969) [Ukrainian records].

Rhytisma umbonatum (Hoppe ex Wallr.) Rabenh. [click here for picture]. Status. Native; 2 records; no information on abundance. Months. No information. Regions. No information. Habitat. On living and, later, dead leaves of Salix purpurea. Notes. The fungus colonizes living leaves, causing typical 'tarspots', but apparently never killing the plant; probably always fruiting within 12 months of leaf death; the best way to find ripe ascomata of this species and Rhytisma salicinum is to locate a tree bearing many stromata in autumn, when the stromata are prominent, then to revisit the same tree the following spring; this has almost never been done, and most specimens in most collections are of stromata on green leaves, with no ripe ascomata. Worldwide. Widespread on leaves of various species of Salix in Europe and North America, with one record from India; apparently nowhere as common as Rhytisma salicinum. References. Cannon & Minter (1986) [description]; Minter & Dudka (1996) [Ukrainian records]; Morochovskii, Zerova, Lavitskaya & Smitskaya (1969) [Ukrainian records].