Species within a genus

aurum, = gold;
-atus, = indicates possession or likeness.
auro, auratus, = to overlay with gold, to gild; furnished, overlaid or ornamented with gold, gilded, gilt.
(flecked with gold)
(ld, BL)

Now Tetraria bolusii.
(PS)

Now Tetraria compar.
(PS)

crassus, = solid, thick, dense, fat, gross, etc.
(ld)

Now Tetraria cuspidata var. cuspidata.
(PS)

gracilis, gracilus, = thin, slight, slender, slim, meagre, lean; simple, plain, unadorned;
-imus, = (superlative), very.

(ld, BL)

lingua, = the tongue;
-ula, = diminutive;
ligula, lingula, = a little tongue, the tongue of a shoe, a shoe trap, shoe-latchet; a spoon or ladle;
-atus, = indicates possession or likeness.
lingulatus, = tongue-shaped, lingulate.
(strap-shaped – probably refers to the shape of the bracts or dried elongated tips of the lip)
(ld, BL, Co)

niger, -gra, -grum, = black, sable, dark, dusky;
(black, especially glossy black)
nigrico, = to be blackish;
-icans, = indicates process of becoming or resemblance sometimes so close as to be almost identical.
nigricans, = blackish, swarthy.
(blackish, swarthy)
(ld, BL)

purpura, = purple colour, purple;
-ascens, = indicates process of becoming, hence not fully achieved resemblance, often expressed by the termination ‘-ish’.
purpurasco, = to grow purple, become a purple colour.
(ld, BL)

quattuor, quad-, = four;
angulus, = an angle, a corner;
quadangulus, = four cornered, quadrangular;
-alis, -aris, = belonging or pertaining to, resembling, provided with.
(four-angled)
(ld, BL)