A Grammatical Dictionary of Botanical Latin

Tetrad (Eng.noun): tetras,-adis (s.f.III), abl.sg. tetrade, nom. & acc. pl. tetrades, gen.pl. tetradum: four coherent pollen grains; a group of 4 developing spores (formed as a result of meiotic division of a spore mother cell); due to tardy separation, mature spores may be ellipsoidal, angular, or kidney-shaped (C&A) [> Gk. tetras,-adis (s.f.III), a tetrad; the number four, a quaternion [L. quaternium,-ii (s.n.II)] or tetradion (s.n.II) [L. tetradium,-ii (s.n.II)]; see dyad, monad, triad; see trilete;

(After Radford, et al. 1974):

NOTE: possibly also tetradum,-i (s.n.II), abl.sg. tetrado, following Stearn (1983).

- tetras tetraedrica, abl. sg. tetrade tetraedrica, a tetrahedral tetrad (pollen of Ericaceae, Droseraceae).

- tetras tetragona, abl. sg. tetrade tetragona, a tetragonal tetrad, as in pollen grains of Annonaceae.

- siliqua sessilis, compressa v. subtetragona, angusta v. latiuscula (B&H), the silique sessile, compressed or somewhat tetragonal, narrow or somewhat broad.

- tetras rhombea, abl. sg. tetrade rhombea; tetras rhombica: rhomboidal tetrad, as in pollen grains of Meconopsis.

- tetras linearis, abl. sg. tetrade lineari: as in pollen grains of Typha (after Radford, et al. 1974).

- tetras sporica, abl. sg. tetrade sporica, spore-tetrad

- diameter cellularum transversalis in eremobiis et binatim conjunctis longitudinalem paullo superans, in cellulis tetradum altera alteram aequans (Braun), the transverse diameter of the cells in eremobia [i.e. solitary-living species], and [those] joined in pairs, somewhat overtopping the length, in the cells of the triad the one equalling the other.

Spore Mother Cell: “one of the cells of the archespore of a spore-bearing plant whose final divisions result in the production of a spore and usually of a tetrad of spores” (WIII).

Tetraspora,-ae (s.f.I), q.v.: a spore formed by division of the spore-mother-cell into four parts” (Jackson); see tetraspore.

Tetrads are clusters of four rounded bacterial cocci arranged within the same plane (e.g. Micrococcus sp.).

Tetrad scar, the ridge deriving from coherence with other sores produced from the same mother (primary) cell: cicatrix,-icis (s.f.III) tetradica (adj.A), abl. sg. cicatrice tetradica.