A Grammatical Dictionary of Botanical Latin

Thallus,-i (s.m.II), abl.sg. thallo, nom. pl. thalli, acc. pl. thallos, dat. & abl. pl. thallis: thallus, the vegetative body of a thallophyte; “a fusion of root, stem, and leaves into one general mass” (Lindley); (in lichens) the thallus may be referred to as the trunk (truncus,-i (s.m.II), q.v.) (Jackson); (in bryophytes) “a more or less flattened gametophyte, not differentiated into a stem and leaves” (Magill 1990); (in algae) the plant body of an alga” (A&D); (fungi) “a general term for the vegetative portion of a nonvascular plant, particularly the Thallophytes; of the fungi, the entire assimilative phase of the individual” (S&D) [> Gk. thallos (s.m.II), a young shoot, twig, a young or green branch; branch generally]; see phycoma,-atis (s.n.III); see prothallium,-ii (s.n.II).

“A plant body that is characteristic of the thallophytes, that does not grow from an apical point, shows no differentiation into distinct tissue systems (as vascular tissue) or members (as stems, leaves, or roots) or is composed of members resembling and performing many of the functions of but not homologous with those of the higher plants, and that may be simple or branched, may consist of filaments or plates of cells, and may vary widely in form and size from microscopic one-celled plants to complex foliated or arborescent forms (as in some of the larger marine algae” (WIII).

- thalli ante divisionem, divisione, post divisionem bifurcati, thalli before division, at division, after division bifurcate.

- thallus epiphloeodes crustaceus uniformis tenuis (60-80 um crassus) late expansus, substratum arcte obducens, griseus opacus, sorediis et insidiis destitutus, in margine linea obscuriore non cinctus, thallus growing on the surface of bark crustaceus uniform thin (60-80 um thick) broadly outspread, the substratum tightly covering, gray opaque, by soredia and insidia forsaken (i.e. lacking soredia and insidia), at the margin by a darker line not encircled.

- thallus pro maxima parte endolithicus, thallus for the most part endolithic (growing within stone).

- thalli superficies trichomatibus instructa, of the thallus the upper side with trichomes arrayed; cf. phycoma (Stearn).

- thallus tener et tenuis aetate durior et crassior, the thallus delicate and thin, with age harder and thicker.

Note: frons, gen.sg. frondis (s.f.III), i-stem, gen. pl. frondium, ‘foliage,’ may be used of the thallus in Hepaticae, where there is little or no differentiation between stem (caulis)and leaves (folia); see frons, gen. sg. frondis (s.f.III);

- frons 3 mm longa, longe furcata, furcis divergentibus, angustis, crassis, 4 plo latioribus quam altis antice posticeque aequaliter plano-convexis, apice rotundatis, marginibus obtusis (Steph.), the frond 3 mm long, longly furcate, with the forks divergent, narrow, thick, 4-times wider than high, antically and postically equally plano-convex, rounded at the apex, with the margins obtuse [note: ‘wider than high’ is in reference to the thickness of the frond].

- thalli in axe principali ramos multiplices producentes, thalli on the principle axis producing multiple branches.

Note: frons, gen.sg. frondis (s.f.III) may also refer to the thallus of a foliaceous lichen:

- [lichen] lichen fronde [=thallus] rotunde lobata, inferne nigerrima glebosa (Necker), lichen frond [i.e. thallus] rounded-lobed, below very (glossy) black, lumpy.

NOTE: [as trichoma] “the filamentous thallus of Algals, as Conferva” (Lindley); “1. the filamentous thallus of such Algae as Conferva (Lindley); 2. the filaments in Nostoc” (Jackson): trichoma,-atis (s.n.III), abl.sg. trichomate, q.v.; see trichome.

Note: the front or adaxial side of a thallus may be the venter,-tris (s.m.III), abl. sg. ventre, q.v., the back, lower or outer (adaxial) side may be the dorsum,-i (s.n.II), abl. sg. dorso:

- thallus ad 15 cm latus, axillis rotundatis; dorsum thalli pallide glaucescens, reticulato-costatum scrobiculatumque; sorediis destitutum, costis et marginibus dense isidiosis, isidiis cylindricis; venter thalli brunneus aut albidus, thallus to 15 cm wide, with rounded axils; the back of the thallus pale greenish-blue, reticulate-coastate and scrobiculate (minutely pitted); lacking soredia, with costae and margins densely isidiose, with cylindric isidia; the adaxial side (front) of the thallus brown or white.

Blastema,-atis (s.n.III), q.v., abl. sg. blastemate, nom. & acc. pl. blastemata: “(obsol.) the thallus of a lichen” (Lindley).

Filament Thallus = Fruticose Thallus, “a Lichen having a shrub-like thallus” (Jackson): thallus,-i (s.m.II) fruticosus (adj.A), abl. sg. thallo fruticoso.

growing on the thallus: thallicola,-ae (s.f.I), abl. sg. thallicola.

Involucrum,-i (s.n.II), abl.s g. involucro: (in bryophytes) “the tissue of the thallus in Anthoceroteae, grown up and overarching the embryo, afterwards pierced by the lengthening sporogonium” (Jackson).

lacking a thallus [lichens]: ecrustaceus,-a,-um (adj.A): “destitute of thallus, applied to Lichens” (Jackson); see crustaceus,-a,-um (adj.A).

Lorlulum,-i (s.n.II), abl. sg. lorlulo, q.v.: “the filamentous and branched thallus of some Lichens” (Jackson).

Lorum,-i (s.n.II), q.v., abl. sg. loro, nom. & acc. pl. lora: used in reference to a strap-shaped thallus in lichens.

Proembryo,-onis (s.m.III), abl. sg. proembryone, nom. & acc. pl. proembryones, dat. & abl. pl. proembryonibus: proembryo “the reproductive part of a spore. The youngest thallus of a Lichen” (Lindley).

Prothallus, q.v., the small, usually flat, thallus-like growth resulting from germination of a spore; the gametophyte generation in the alternation of generations: prothallus,-i (s.m.II).

Pseudothallus,-i (s.m.II), abl. sg. pseudothallo: a false thallus.

Thallus,-i (s.m.II) crustaceus, abl. sg. thallo crustaceo: “in the lichens, a thallus that forms a flat crust on or in the substratum, adhering firmly by its entire lower surface so that it cannot be separated without injury, same as ‘thallus lepodes’” (S&D).

Thallus filamentosus,-a,-um (adj.A) = Thallus fruticosus.

Thallus,-i (s.m.II) frondosus (adj.A), abl.sg. thallo frondoso: (fungi) “the frondose thallus of lichens” (S&D).

In lichens: frondose thallus = “same as ‘foliaceous thallus’ (S&D) [thallus foliaceus] = Thallus placodes, “the foliaceous thallus of lichens” (S&D).

Thallus,-i (s.m.II) fruticosus, abl. sg. thallo fruticoso: “in lichens, a thallus attached by one point only or by a narrow base to the substratum, from which it grows upward as a simple or more or less branched, shrublike body; ‘thallus fruticulosos;’ also called ‘filamentous thallus’” (S&D) [thallus filamentosus,-a,-um (adj.A). Thallus thamnodes = “the fruticose thallus” (S&D).

Thamnium,-ii (s.n.II), abl. sg. thamnio: “(obsol.) the branched bush-like thallus of Lichens” (Lindley).

Truncus,-i (s.m.II), abl.sg. trunco: “1. the main-stem or trunk of a tree; 2. in Lichens, the thallus” (Jackson)

NOTE: Proembryo,-onis (s.m.III), abl. sg. proembryone, nom. & acc. pl. proembryones, dat. & abl. pl. proembryonibus: proembryo, “The youngest thallus of a Lichen” (Lindley).

thallus-like: thalliformis,-e; see thallosus,-a,-um (adj.A).