Trigonidium
(from trigona, a triangle, and eidos, like; alluding to the triangular form of several parts of the plants). ORD. Orchideae. A small genus (seven or eight species have been described) of curious, stove, epiphytal Orchids, inhabiting tropical America. Flowers rather large, shortly pedicellate within spathaceous bracts; sepals sub-equal, connivent or coherent at base in a triquetrous, turbinate tube, free above, spreading; petals similar, but much smaller; lip rising from the base of the column, erect, much shorter than the sepals, the lateral lobes erect, embracing the column, the middle one spreading; pollen masses four; scapes many-sheathed, one-flowered. Stem very short, mostly pseudo-bulbous. A selection of the species known in gardens is given below. They thrive on blocks, or in baskets of peat, fibre, and sphagnum, and like a fairly light position, near the glass. T. acuminatum (taper-pointed). fl. dull straw-colour externally, within elegantly pencilled with rich brown; sepals acuminate, recurved at apex; petals oval-lanceolate, mucronate. l. linear, longer than the peduncles. Pseudo-bulbs ovate, acute, sulcate, one-leaved. Demerara, 1834. T. Egertonianum (Sir P. Egerton's). fl. pale liver-colour, dashed and veined with brown; sepals acute, the lateral ones reflexed; petals slightly acute. l. narrow, often 1 1/2ft. long, ensiform. Pseudo-bulbs clustered, oval, compressed, two-leaved. Honduras, 1834. A very distinct species. T. obtusum (obtuse).* fl., sepals reddish-yellow, obovate; petals white, veined with rose, brown at apex, obtuse; lip white, tubercled at back, the lateral lobes red-margined, the middle one yellow in front. l. linear-lanceolate. Demerara, 1834. (B. R. 1923.) T. tenue (slender). fl. brewnish-purple; sepals reflexed, very acuminate; lip obtuse, glabrous, reflexed at apex; scape erect. slender. l. ensiform, very acute, longer than the scape. Pseudo bulbs oval, compressed, one-leaved. Demerara, 1836.