What is thalloid

Thallus is a related term of thalloid. In botany terms the difference between thalloid and thallusis that thalloid is of a plant, alga, or fungus lacking complex organization, especially lacking distinct stems, roots, or leaves while thallus is any plant body lacking vascular tissue. As an adjective thalloidis of or pertaining to a thallus. As a noun thallus isan undifferentiated plant body, such as in algae.

\( \newcommand\) • • • • • • Marchantia, a 'complex, thalloid' liverwort Marchantia is one of the most commonly encountered liverworts. It has a wide distribution (arctic to tropics) and is relatively large and with a distinctive form. It is often encountered in seeps near steep rocky outcrops next to brooks and streams. Marchantia gametophyte, a prostrate (ground-hugging) thallus that bifurcates (forks) as it grows. Taxonomy and phylogeny Marchantia is in the Phylum Hepatophyta in the Plant Kingdom. In the past, the three groups of non-vascular plants (mosses, liverworts and hornworts) were grouped together into some taxonomic entity, often a phylum, but recent studies have supported placing the three groups into three separate phyl a , reflecting a view that the liverworts, mosses and hornworts are not obviously connected with each other, other than all being plants. Structure (Gametophyte)—Of all the plant groups, the liverworts show the most diversity in form. While some liverworts bear a resemblance to mosses, having a stem axis with appendages ( 'leaves' ), Marchantia is representative of a group of liverworts described as having 'complex thalloid' structure, consisting of a flattened body (a thallus) that generally spreads across the ground surface and is differentiated into a top and bottom. Marchantia is characterized by repeated branching into two parts. The thallus has multiple layers of cells. The top layer has permanently open pores (visible to the naked eye a...

Hornworts, Phylum Anthocerotophyta The name Anthocerotophyta means 'horn flower plant'. These strange plants, called the hornworts, get their name from the horn-like sporophytes they produce. Hornworts have a flattened thalloid gametophyte, out of which grow their long photosynthetic sporophytes (Figure \(\PageIndex\): Hornworts growing in a cluster. The gametophytes are the leafy green material growing closer to the surface. The sporophytes are the emergent structures. The appearance of the sporophytes is what gives the hornworts their name. Photo by Maria Morrow, Gametophyte Morphology Hornwort gametophytes are exclusively thalloid, often with compartments of mutualistic cyanobacteria from the genus Nostoc. Cells within the gametophyte are monoplastidic (Figure \(\PageIndex\)), containing one large chloroplast in each cell. Similar to the green algae, hornwort chloroplasts contain a pyrenoid where starch storage is concentrated. On the exterior of the thallus, simple pores allow for gas exchange. Unlike stomata, simple pores have no guard cells, meaning they are permanently open. Some hornwort species house colonies of Nostoc within the gametophyte thallus, providing access to nitrogen fixed by the cyanobacterial colony. Figure \(\PageIndex\): This image of part of a Phaeoceros proskaueri thallus shows the cells of the gametophyte each containing a single large plastid (monoplastidic). The second photo is a cropped view with a single cell encircled. A line indicates the ...

\( \newcommand\) • • • • Gametophyte morphology • Leafy liverworts have leaves arranged in a flat plane with a set of smaller underleaves • Thalloid liverworts have no leaves • Liverwort cells have multiple chloroplasts • Simple pores allow for gas exchange (no guard cells, meaning pores are permanently open) • Asexual clones, called gemmae, are sometimes produced • Sporophyte morphology • Leafy liverworts produce single sporangium at the end of a seta (often fragile, transparent) • Marchantia, a thalloid liverwort, develops complex structures called where gametangia are produced Leafy Liverworts Cut off the end of a leafy liverwort and make a wet mount or obtain a prepared slide to view under the compound microscope. Draw the specimen below and indicate the three different rows of leaves (two in one plane, and a row of smaller underleaves running beneath the stem). Still under the compound microscope, observe one of the leaf cells. Can you tell how many chloroplasts are in it? Draw this cell in the space below and label the chloroplasts and any other features you recognize. Thalloid Liverworts: Marchantia If available, observe a Marchantia polymorpha gametophyte under the dissecting scope. Look for simple pores, rhizoids, archegoniophores, antheridiophores, and gemmae cups containing asexual clones of the gametophyte, called gemmae. Label the bolded features in the life cycle diagram. Marchantia life cycle: Figure \(\PageIndex\): Marchantia sporophyte

• Беларуская • Български • Català • Čeština • Cymraeg • Dansk • Deutsch • Eesti • Español • Esperanto • Euskara • فارسی • Français • Gaeilge • Galego • Ido • Bahasa Indonesia • Íslenska • Italiano • עברית • ქართული • Latina • Latviešu • Македонски • Nederlands • 日本語 • Norsk bokmål • Norsk nynorsk • Oʻzbekcha / ўзбекча • Polski • Português • Română • Русский • Slovenčina • Slovenščina • Српски / srpski • Srpskohrvatski / српскохрватски • Suomi • Svenska • Türkçe • Українська • Tiếng Việt • 中文 Thallus (plural: thalli), from θαλλός ( thallos), meaning "a green thalloid, thallodal, thalliform, thalline, or thallose. A thallus usually names the entire body of a multicellular non-moving organism in which there is no organization of the thalloid. Although a thallus is largely undifferentiated in terms of its anatomy, there can be visible differences and functional differences. A The thallus of a The See also [ ] • • References [ ]

In Thalloid (thallose) liverworts have a ribbonlike, or strap-shaped, body that grows flat on the ground. They have a high degree of internal structural differentiation into photosynthetic and storage zones. Liverwort gametophytes have unicellular rhizoids. Liverworts have an alternation of generations similar to that of mosses, and,… classification and distribution •