Development of Adventive Thalli in Umbilacaria Hoffm.

Masumoto

2021

A review of algal (including cyanobacterial) symbionts associated with lichen-forming fungi is presented. General aspects of their biology relevant to lichen symbioses are summarized. The genera of algae currently believed to include lichen symbionts are outlined; approximately 50 can be recognized at present. References reporting algal taxa in lichen symbiosis are tabulated, with emphasis on those published since the 1988 review by Tschermak-Woess, and particularly those providing molecular evidence for their identifications. This review is dedicated in honour of Austrian phycologist Elisabeth Tschermak-Woess (1917–2001), for her numerous and significant contributions to our knowledge of lichen algae (some published under the names Elisabeth Tschermak and Liesl Tschermak).

Section: Acquisition Of New Algal Symbiontsmentioning

confidence: 99%

Lichen algae: the photosynthetic partners in lichen symbioses

Masumoto

2021

“…The rhizines of some species of Umbilicaria [' rhizinomorphs ' of Hannemann (1973)] have been observed to incorporate algal cells sporadically, giving rise to new ' thallyles ' or ' adventive thalli' (Krog & Swinscow 1986;Schuster 1992). The rhizomorphs produced by many squamulose lichens may act in a similar way, bearing new squamules locally where an appropriate photobiont is captured (Wagner & LetrouitGalinou 1988;Sanders 1994).…”

Section: Mycobiont Structures and Prothallic Morphogenesismentioning

confidence: 99%

Thallus Organization and Development in the Fruticose Lichen Aspicilia Californica, with Comparisons to other Taxa

1999

“…Nonetheless, many observations indicate that lichen organography is characterized by great flexibility. The rhizines of some species of Umbilicaria [' rhizinomorphs ' of Hannemann (1973)] have been observed to incorporate algal cells sporadically, giving rise to new ' thallyles ' or ' adventive thalli' (Krog & Swinscow 1986;Schuster 1992). The rhizomorphs produced by many squamulose lichens may act in a similar way, bearing new squamules locally where an appropriate photobiont is captured (Wagner & Letrouit-Galinou 1988;Sanders 1994).…”

Section: Mycobiont Structures and Prothallic Morphogenesismentioning

confidence: 99%

Thallus Organization and Development in the Fruticose Lichen Aspicilia Californica, with Comparisons to other Taxa

1999

Thallus organization is examined in Aspicilia californica Rosentreter, fruticose lichen known from several localities in central and southern California. The sprawling, terete thallus branches possess a dense central medulla of thickwalled, longitudinally oriented fungal cells. This central tissue emerges at branch apices to form a darkly pigmented fungal tip. Thallus development involves the apical extension of the tip to produce a fungal tissue over which a cylindrical algal layer and cortex will eventually be formed. Apical branches are initiated by furcation entirely within the fungal tip. Lateral branches, emerging from the lichenized thallus, arise as a divergent bundle of elongate fungal cells originating in the medulla. The photobiont appears to play no direct role in initiation of apical or lateral branches. It is concluded that thallus development in A. californica occurs with a relatively low degree of synchrony between mycobiont and photobiont growth, similar to the pattern observed in crustose lichens with prothallic growth. A rather similar type of thallus organization is observed in A. hispida, although in that species mycobiont growth and branch initiation appear to be somewhat more closely associated with algal cell proliferation. A squamulose Aspicilia from central Spain produces rhizomorphs that may sometimes become invested with an algal layer and cortex, resembling the thallus axes of A. californica.