Crossword clues for thallus
The Collaborative International Dictionary
Thallus \Thal"lus\, n.; pl. Thalli. [NL., fr. Gr. ? young shoot or branch, frond.] (Bot.) A solid mass of cellular tissue, consisting of one or more layers, usually in the form of a flat stratum or expansion, but sometimes erect or pendulous, and elongated and branching, and forming the substance of the thallogens.
Douglas Harper's Etymology Dictionary
1829, Latin, from Greek thallos "green shoot, young branch, twig," related to thalia "abundance," thalos "scion, child," ultimately from PIE root *dhal- "to bloom" (cognates: Armenian dalar "green, fresh," Albanian dal' "I sprout," Old Irish duilesc, a type of algae).
Wiktionary
n. 1 (context botany English) An undifferentiated plant body, such as in algae. 2 (context botany English) Any plant body lacking vascular tissue.
WordNet
n. a plant body without true stems or roots or leaves or vascular system; characteristic of the thallophytes
[also: thalli (pl)]
Wikipedia
Thallus (plural: thalli), from Latinized Greek θαλλός (thallos), meaning "a green shoot" or " twig," is the undifferentiated vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called 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 tissues into organs. Even though thalli do not have organized and distinct parts ( leaves, roots, and stems) as do the vascular plants, they may have analogous structures that resemble their vascular "equivalents". The analogous structures have similar function or macroscopic structure, but different microscopic structure; for example, no thallus has vascular tissue. In exceptional cases such as the Lemnoideae, where the structure of a vascular plant is in fact thallus-like, it is referred to as having a thalloid structure, or sometimes as a thalloid.
Although a thallus is largely undifferentiated in terms of its anatomy, there can be visible differences and functional differences. A kelp, for example, may have its thallus divided into three regions. The parts of a kelp thallus include the holdfast (anchor), stipe (supports the blades) and the blades (for photosynthesis).
The thallus of a fungus is usually called a mycelium. The term thallus is also commonly used to refer to the vegetative body of a lichen. In seaweed, thallus is sometimes also called ' frond'.
The gametophyte of some non-thallophyte plants -- clubmosses, horsetails, and ferns is termed " prothallus".
Thallus was an early historian who wrote in Koine Greek. He wrote a three-volume history of the Mediterranean world from before the Trojan War to the 167th Olympiad, c. 112-109 BC. Most of his work, like the vast majority of ancient literature, has been lost, although some of his writings were quoted by Sextus Julius Africanus in his History of the World.
The works are considered important by some Christians because they believe them to confirm the historicity of Jesus and provide non-Christian validation of the Gospel accounts: a reference to a historical eclipse, attributed to Thallus, has been taken as a mention of the worldwide darkness described in the Synoptic gospels account of the death of Jesus, although an eclipse could not have taken place during Passover when this took place. Most modern scholars see the darkness as a literary creation rather than a historical event.
Thallus of Miletus , was an epigrammatic poet, five of whose epigrams are preserved in the Greek Anthology. Of these the first is in honour of the birthday of a Roman emperor, or one of the imperial family, on which account Bovinus supposes the poet to be the same person who is mentioned in an extant inscription as a freedman of Germanicus. The name is given in various forms: Thalos, Thyelaus, Thyillus ; it may have arisen from a confusion between the poet and the celebrated philosopher, Thales of Miletus. The name Thallos occurs frequently in inscriptions from Attica and Ionia.
Thallus is an undifferentiated vegetative tissue of some non-mobile organisms.
Thallus may also refer to:
- Thallus (historian), the chronologer/historian
- Thallus (poet), the Roman era Greek epigrammatist
Usage examples of "thallus".
It reproduced like the vegetable cryptogams, especially the Pteridophyta, having spore cases at the tips of the wings and evidently developing from a thallus or prothallus.
Fungal hyphae occur in the rhizoids and in the cells of the lower region of the thallus of many liverworts, as in the endotrophic mycorhiza of higher plants.
Others appeared to be parasites, sending complex veins ramifying through the thalli of their victims.
In the latter they are protected by special concave scales, while in the Anthocerotaceae they occupy some of the mucilage slits between the cells of the lower surface of the thallus.
The Anthocerotales are a small and very distinct group, in which the gametophyte is a thallus, while the sporogonium possesses a sterile columella and is capable of long-continued growth and spore production.
The small thallus bears the antheridia and archegonia, each of which is surrounded by a tubular involucre, on the upper surface of distinct individuals.
The necks of the archegonia hardly project above the general surface of the thallus.
The dorsiventral thallus is constructed on the same plan throughout the group, and shows a lower region composed of cells containing little chlorophyll and an upper stratum specialized for assimilation and transpiration.
The lower members of the Jungermanniales are also thalloid, but the thallus never has the complicated structure characteristic of the Marchantiales, and progress is in the direction of the differentiation of the plant into stem and leaf.
The Marchantiales are a series of thalloid forms, in which the structure of the thallus is specialized to enable them to live in more exposed situations.
Sometimes adaptations to protect the plant during seasons of drought, such as the rolling up of the thallus in many xerophytic Marchantiales, can be recognized, but more often a prolonged dry season is survived in some resting state.
It reproduced like the vegetable cryptogams, especially the Pteridophyta, having spore cases at the tips of the wings and evidently developing from a thallus or prothallus.
Squinting in the bruised light, Molly saw patches of a blackish thallus, flecked with green, growing on the trunk in crustlike forms.
As it flows it takes the forms of sappy leaves or vines, making heaps of pulpy sprays a foot or more in depth, and resembling, as you look down on them, the laciniated, lobed, and imbricated thalluses of some lichens.