Archivos de diario de febrero 2022

02 de febrero de 2022

Powder Horn Lichens Clarified

Quotation from the Notes from this link:

Lichen terms used in the quote, and their meaning:
thallus Not in the quote below. Lichens, whether tiny and dust-like or large and dinner-plate-like, or ribbon-like, or shrub-like, have the main body made of a stacked layer of cells called a "thallus". The thicker the stack, the more differentiated the cell layers tend to be - no surprises there.
squamule = small thallus: Note: All lichens have a thallus. The Cladonia species are small lichens and thus have small thalli, and lichenologists call these small thalli "squamules".
podetium (plural = podetia) You may know the word "podium", and a podetium might as well be called a podium [autocorrect strongly agrees - try writing the word "podetium" and see what happens!]. The Cladonia species of lichens hold/present their spore-bearing structures at the end of a podium, sorry, podetium. The shape of the podetium varies from species to species, and can be useful in identification.
corticate like rough tree bark
rugose furrowed, like corduroy cloth
soredia A botanist would use the term "gemmules", for soredia. Soredia (and gemmules) are packets of cells that are clones (have exactly the same genetic material) as the lichen (plant); each soredia (gemmule) is capable of growing into a new lichen (plant). Soredia (and gemmules) are a means by which the lichen (or plant) clones itself.
soralia A structure that produces soredia. The shape of the structure can be useful in identification.
farinose powdery texture of wheat flour
erumpent Eruptive; bursting forth through the surface. So why not just say eruptive?

"Cladonia coniocraea and C. ochrochlora are morphologically very similar, and some authors are inclined to unite them. The present treatment is provisional. The squamules of C. coniocraea are always deeply incised, whereas the margins of the squamules of C. ochrochlora can be nearly entire. Cladonia coniocraea is usually found without cups, but C. ochrochlora rarely lacks them completely. The base of the podetium in C. coniocraea is only thinly corticate, while the cortex of C. ochrochlora is thick, extends beyond the immediate base, and is often longitudinally rugose. The soredia of the present taxon are usually farinose, rarely occurring in small, diffuse soralia; soredia in C. ochrochlora are variable, but are usually larger than those of C. coniocraea, and often largely occur in well defined, erumpent soralia. The podetia of C. coniocraea are greenish rather than gray, fairly slender, usually not more than 1.5 mm diameter, and are usually straight. The podetia of C. ochrochlora have a grayish tint, are generally thicker, and are often somewhat branched and twisted (Hammer 1993)."

"The base of the podetium in C. coniocraea [Common Powderhorn] is only thinly corticate, while the cortex of C. ochrochlora is thick . . ."

Translation by yours truly . . .

The base of the horn-like podium in Common Powderhorn, Cladonia coniocraea has only a thin bark (is often smooth), while the bark of the Smooth-footed Powderhorn, C. ochrochlora is thick. Yes, you read that correctly, and yes, I translated it correctly. The Smooth-footed Powder Horn actually has a rough foot, whilst the Common Powderhorn tends to have a smooth foot. It is all clear as mud.

If a common name is to be helpful, it should be, well, helpful.

Publicado el 02 de febrero de 2022 por mjpapay mjpapay