caloplaca coralloides lichen taxonomy

Taxonomy

The taxonomy of lichens is a shifting and uncertain system. Some scientists categorize lichens in a separate division of fungi, Lichenes, while others want lichens to be spread out among the different divisions of the kingdom Fungi along with un-lichenized fungi based on shared characteristics such as the structure of reproductive apparatus. The taxonomy of lichens, and of Caloplaca coralloides in particular, is likely to change in the future. For this page, I have decided to follow the taxonomic ordering of C. coralloides that is given by the Integrated Taxonomic Information System (ITIS) , which is the USDA's taxonomic system.

Caloplaca coralloides (Tuck.) Hult., Hedgwigia 35:187. 1896.

Kingdom	Fungi
Division	Ascomycota
Subdivision	Pezizomycotina
Class	Lecanoromycetes
Order	Lecanorales
Suborder	Teloschistineae
Family	Teloschistaceae
Genus	Caloplaca
Species	coralloides

Lichens are classified by their fungal components. The name given to lichens is actually the name of its fungal component. Therefore, the identity of the photobiont does not determine the taxonomic grouping of a lichen.

The taxonomic classification of C. coralloides is as follows:

Kingdom: Fungi: have non-motile bodies made up of apically elongating filaments called hyphae, a life cycle with sexual and asexual reproduction, haploid thalli resulting from zygotic meiosis, and heterotrophic nutrition. Spindle pole bodies, not centrioles, usually are associated with the nuclear envelope during cell division. The characteristic wall components are chitin (beta-1,4-linked homopolymers of N-acetylglucosamine in microcrystalline state) and glucans primarily alpha-glucans (alpha-1,3- and alpha-1,6- linkages) (Griffin, 1993 as cited in Blackwell, 2005).

Division: Ascomycota: is the division of sac-forming fungi. This is the largest group of fungi and at least 15,000 of them form lichens. These fungi are grouped together because they hold their spores in sacs called asci, which are organized within the fertile tissue. However, some lichenologists and mycologists think that lichens should be grouped together into a division of their own, Lichenes.

Subdivision: Pezizomycotina

Class: Lecanoromycetes

Order: Lecanorales: fruiting bodies are apothecia.

Family: Teloschistaceae: This family is made up of crustose, foliose and fruticose lichens that have lecanorine apothecia (lecanorine means that the margin of the apothecium contains photobionts and is similar in color and texture to the thallus) with (usually) orange apothecial discs (anthraquinones present). Spores are colorless and polarilocular. Members of the family Teloschistaceae usually live on trees and rocks from arctic to temperate regions. The genera within the family Teloschistaceae are Caloplaca, Blasteni, Fulgensia, Gasparrinia, Teloschistes and Xanthoria.
   -Lichen families are generally characterized by the structure of their fruiting bodies.

Genus: Caloplaca: is a large heterogeneous group of mostly crustose species. All of the species of Caloplaca have orange apothecial disks that react deep red/purple with KOH (because they have anthraquinones); sometimes the thallus and vegetative structures also react deep red/purple with KOH. Spores are colorless, two-celled or polarilocular.
     -Lichen genera can be told apart by the color and septation of their ascospores.

Species: coralloides: is a dwarf fruticose growth form. The thallus is greenish yellow to orangeish yellow in color. The thin yellow prothallus is sometimes present around the base of branches. The branches are terete and dichotomous to subdichotomously branched. The thallus of C. coralloides is nodulose and has pseudocyphellae. Algae are present in scattered clumps below the cortex and hypothecium. Apothecia can be absent or present, but are common and 0.4-2.0 mm in size. Apothecia are present terminally or laterally on branches. The apothecial disc can be concave, flat or convex and is darker orange than the rest of the thallus. The hymenium (fertile layer in apothecia) is 65-90 um thick; paraphyses (vertically oriented hyphae in hymenium) are mostly unbranched but occasionally branched. The spores of C. coralloides are polaribilocular or two-celled, ellipsoid and colorless. Pycnidia mostly present and abundant and are immersed to somewhat raised, orange, and slightly glossy. The major cortical pigment is parietin, but C. coralloides also has emodin, teloschistin, parietinic acid and fallacinal. C. coralloides is confined to the coast and grows in the lower part of the supralittoral zone mostly on vertical surfaces of hard rocks. C. coralloides is not sorediate.
    - Lichen species are delineated somewhat randomly by the structure of the ascocarp and vegetative characters. The more complex foliose and fruticose lichens are usually separated by the presence or absense of soredia, isidia, cilia, pseudocyphellae and lobules, and by the type of rhizines, the structure of the exciple, spore size and septation and chemistry.

The Photobiont: Trebouxia

The green algal component of C. coralloides is most likely Trebouxia, the most common green algal photobiont in lichens. The taxonomy of Trebouxia is as follows:
K: Protista
D: Chlorophyta
C: Chlorophyceae
O: Chlorococcales
F: Chlorococcaceae
G: Trebouxia
S: (unknown)

Cyanobacteria can also be photobionts in lichens (although this is not the case in C. coralloides). The most common cyanobacteria lichen photobiont is Nostoc, which is found in most jelly lichens.

Caloplaca coralloides

Taxonomy

The Photobiont: Trebouxia