A Grammatical Dictionary of Botanical Latin

Operculum,-i (s.n.II) abl. sg. operculo, nom.& acc.pl. opercula, gen.pl. operculorum, dat.& abl.pl. operculis; “various lids and flaps pertaining to plants, algae, and fungi” (Wikipedia, June 2019); “the lid of anything, as in the pitcher [ascidium] of Nepenthes or the fruit of Lecythis; more especially the lid of the spore-case [i.e. capsule] of Urn-mosses. A deciduous lid, which closes up the foramina of some polen grains” (Lindley); “a lid; the upper portion of a circumscissile capsule” (Fernald 1950); lid, operculum, the lid covering the mouth of a capsule, often separated by an annulus of differentiated cells making the line of dehiscence, in mosses, falling at maturity when spores are released; the (deciduous) cap on any hollow structure dehiscing circumscissely; the upper part of a pyxis, q.v., the lower constituting the urn, q.v.; see lid, systylus,-a,-um (adj.A); syn. integumentum, q.v., tegmen,-inis (s.n.III), q.v.;

Willdenow: (p.135)

“The case, (theca), is the fruit of the frondose Musci. It is a dry fruit that opens in the middle with a lid, and is furnished with particular parts.

The Lid, (operculum,-i (s.n.II)), is a round body that closes the opening of the theca, and when the seed is ripe falls off- It is:

1. Convex, (operculum convexum), that has a raised or arched surface.

2. Conical, (operculum conicum), that is wide below, but runs above into a round point.

3. Acute, (operculum acutum), that is wide below, but above grows gradually into an acute point.

4. Acuminated, (operculum acuminatum ), when the upper part is drawn out into a very long point.

5. Flat, (operculum planum ), when the operculum is quite flat.

6. Mucronate, (operculum mucronatum), when the operculum is quite flat, but on the upper side, in the centre, has a bristle-like point.”

NOTE: sometimes in botany ‘calyptra’ may be used for ‘lid,’ but in mosses calyptra has a specific meaning; see calyptra.

- [Myrtus] sunt species novi generis, mihi Calyptranthes ab Eugenüs & Myrtis distinctissimi: calyce truncato, defectu petalorum, eorumque loco Operculo calyptrae instar genitalia tegente (Swartz), they are species of a new genus by me Calyptranthes very distinct from Eugeniis and Myrtis: by the truncate calyx, by the lack of petals, and by an operculum, in their place [i.e. the petals] like a calyptra [i.e. a veil or cap] covering the sex organs.

- operculum antherae subcordatum lateribus inflexum (F. Mueller), the operculum of the anther subcordate, inflexed on the sides.

- antherae oblongae, 4-loculares, (duobus loculïs utroque latere, quorum opercula erecta persistunt, quasi cornicula (Swartz), anthers oblong, 4-locular, (with the two locules on each side, the opercula of which erect, persistent, as if little horns).

- capsula globosa, ovoidea v. oblonga, sub vertice poris transversis inter placentas dehiscens, operculis brevissime valva?formibus (B&H), the capsule globose, ovoid or oblong, below the top dehiscing with transverse pores between the placentas.

- operculum conicum oblique rostratum capsulam longitudine fere aequans, operculum conical obliquely beaked the capsule in length almost equalling.

- ascidia peristomio applanato operculum versus expanso, operculo ovato, pitchers with the peristome flattened towards the lid expanded, with the lid ovate (Stearn 1983).

- operculo thecae dimidium metiente, with the operculum measuring the half of the theca.

- theca operculo brevi, conico, cartilagineo obtecta, theca covered by a short, conic, cartilagineous operculum.

- theca cinnamomea, post operculi delapsum sub ore paullulum constricta (Mitten), theca cinnamon-colored, after the falling away of the operculum somewhat constricted below the mouth.

- operculum recens paulo concavum, exsiccatione patellare (F. Mueller), the fresh operculum somewhat concave, upon drying out, saucer-shaped.

- (moss) annulo (qui semper adest) cum operculo deciduo (Austin), with the annulus (which is always present) deciduous with the operculum.

Conjunctorium,-ii (s.n.II), abl. sg. conjunctorio: “(obsol.) the operculum of the spore-case of an Urn-moss” (Lindley) [> L. conjungo, to bind together, join, unite].