A Grammatical Dictionary of Botanical Latin

Protonema, the protoneme, “the confervoid or plate-like growth in the Mosses on which the conspicuous plant is developed as a lateral or terminal shoot” (Jackson); (in bryophytes) “a filamentous, globose or thalloid structure resulting from spore germination and including all stages of development up to the production of one or more gametophores. The protonema is extremely variable as to the amount of chlorophyll present, the degree of obliqueness of its end walls and the degree to which it branches (cf. chloronema and caulonema). In liverworts a globose, short thalloid or filamentous structure generally gives rise to a single gametophore; in mosses the protonema is typically filamentous although Sphagnum, Andreaea and Tetraphis have more or less thallose protonemata. In a few taxa two morphologically distinct protonematal phases occur, a primary protonema and a secondary protonema; e.g. Jubula and Andreaea” (Magill 1990)[> Gk. proto, ‘first’ + nema,-atis (s.n.III) thread or filament]: protonema,-atis (s.n.III), abl. sing. protonemate, nom. & acc. pl. protonemata.

NOTE: protothallus,-i (s.m.II) appears to have been an early term for protonema; see protothallus,-i (s.m.II).

NOTE: also the name of a genus of algae: Protonema,-atis (s.n.III) Agardh, “from protos, first, and nema, a filament; in allusion to the simplicity of structure. Confervaceae” (Paxton).

Caulonema,-atis (s.n.III), abl. sg. caulonemate, nom. & acc. pl. caulonemata: (in bryology) “the secondary, bud-generating part of the filamentous moss protonema, typically reddish-brown, having few chloroplasts and consisting of long cells with oblique end walls” (Magill 1990).

Chloronema,-atis (s.n.III), abl. sg. chloronemate, nom. & acc. pl. chloronemata: (in bryophytes) “the primary photosynthetic part of the moss protonema, typically green, having numerous chlorolasts and consisting of short cells with perpendicular end walls” (Magill 1990).

Prothallial sporeling: “applied to small thalloid protonema; e.g. Sphagnum” (Magill 1990): protoplasma,-atis (s.n.III) thalloideum (adj.A), abl. sg. protoplasmate thalloideo; see sporeling.

Regenerate protonema (in bryology) “protonemata arising from a mature structure; e.g. broken leaves, stems or setae of mosses” (Magill 1990): protonema,-atis (s.n.III) regenerans (part.B), abl. sg. protonemate regenerante; protonema regenerationis (gen.sg. regeneratio, regeneration); protonema secondarium (adj.A).

Sporeling: “a young plant from a germinated spore” (Jackson); “a young new individual developed from a spore; usually, a young sporophyte; prothallium” (WIII); (in bryophytes) “all structures developed between the germination of the spore and the formation of the adult gametophore; includes the protonema (variously differentiated) and the juvenile gametophore (in some leafy liverworts characterized by pendulum leaf-segmentation” (Magill 1990): prothallium,-ii (s.n.II), abl. sg. prothallio.