A Grammatical Dictionary of Botanical Latin

triangular (with three angles): triangularis,-e (adj.B), triangulatus, -a,-um (adj.A), triangulus,-a,-um (adj.A), trigonalis,-e (adj.B), three-cornered, three angled; trigonus,-a,-um (adj.A); triquetrus,-a, -um (adj.A), deltatus,-a,-um (adj.A), deltoideus,-a,-um (adj.A). "These may be qualified by perdepresse, 'very shallowly', and adverbs listed under depressus, q.v. (Stearn); for Gk. comp. see -gonus,-a,-um (adj.A); see trigonus,-a,-um (adj.A);

“three-edged. Having three acute angles with concave faces; as the stems of many plants” (Lindley).

- folia caulina triangula cruribus aequis, the cauline leaves triangular with the legs equal.

- pinnae trunco multoties angustiores, ambitu late triangulares (Steph.), the pinnae many times narrower than the pinnae, in outline broadly triangular.

- (algae) Sphaerosporae sphaericae aut oblongae, morphosi cellularum peripheriae formatae, in sporas 4 divisione triangula, zonata aut cruciata divisae (Agardh), the sphaerospores either spherical or oblong, formed by a manner of development of the periphery of the cells, divided into 4 spores by a triangular, concentric or cruciate [i.e. in a cross-wise] division.

- (Sphagnum) folia caulina minuta, aequilateraliter vel breviter aequicruri-triangula (Warnst.), stem leaves minute, equilaterally or shortly isosceles-triangular.

-[Sphagnum] cellulae chlorophylliferae sectione transversali aequicruri-triangulae, interiore folii superficie inclusae (Warnst.), the chlorophyllose cells in cross section isosceles-triangular [i.e. with two sides equal], included in the inner surface of the leaf.

triangulato-cuneatus,-a,-um (adj.A): “between triangular and wedge-shaped” (Lindley).