A Grammatical Dictionary of Botanical Latin

Aril (Eng.noun), “a body which rises up from the placenta, and encompasses the seed” (Lindley); an outgrowth of the stalk of the ovule, sometimes resembling a third integument; “1. an expansion of the funicle, arising from the placenta, and enveloping the seed; mace is the aril of the nutmeg;, 2. used by J. E. Smith for the utricle of Carex” (Jackson); “an appendage growing at or about the hilum of a seed” (Fernald 1950) [> “probably from Neolatin arillus, from Medieval Latin, raisin, grape, seed” (WIII); although cf. Lindley: arilliform = bag-shaped; also from the French ‘arille’ (Jackson)]: arillus (s.m.II), abl. sg. arillo, nom.pl. arilli, acc. spl. arillos, dat. & abl.pl. arillis; often treated as a pellicle, q.v.; see arillode; see caruncle, strophiole; see sphalerocarpium,-ii (s.n.II);

- semen pellicula tenui (arillo) obductum, testa subcoriacea (B&H), seed covered with a thin pellicle (the aril), with the seedcoat somewhat leathery.

- semen dorso late concavum, sulco arillo spongioso repleto, seed on the back broadly concave, with the furrow by a spongy aril filled (Stearn).

- arillo integro semen operiente, with an aril, entire, covering the seed.

- arillis papyraceis, with papery arils.

- arillo dimidiam tantum seminis partem obtegente, with the aril covering over only one half part of the seed.

- arillus 0 v. pulposus, aril none or pulpy.

- semina arillo membranaceo v. carnoso fere completo involuta, the seeds enveloped by the membranaceous or fleshy almost perfect aril.

- semen arillo cupulaeformi denticulato cinctum (B&H), seed encircled by a cupuliform, denticulate aril.

- seminibus 1-5, arillo lacero cinctis (B&H), with the seeds 1-5, encircled by a ragged (lacerated) aril.

- semina solitaria, arillo cupulato integro v. lacero suffulta v. fere involuta, seeds solitary, subtended or almost enveloped by a cupulate, entire or ragged aril.

- semen arillo cupulaeformi denticulato cinctum (B&H), the seed girdled by a cupuliform, denticulate aril.

- [Epicharis] semina arillo imperfecto carnoso tecta; cotyledones superpositae; radicula centripeta (B&H), the seeds covered with an imperfect [i.e. rudimentary] fleshy aril; the cotyledons superimposed; the radicle centripetal [i.e. turned inwards towards the axis or center].

(As part of the structure of the seed:) “Besides the [inner and outer integuments usually found in all seeds] we occasionally find on the surface of some seeds an additional integument, which is generally of a partial nature and to which the name of arillus or aril has been given. No trace of this structure is present in the ovule till after the process of fertilisation has taken place. Two kinds of aril have been described, which 1have been respectively called the true arillus, and the false arillus or arillode. These have an entirely different origin thus, the true arillus arises in a somewhat similar manner to the coats of the ovule already described, that is to say, it makes its first appearance around the hilum in the form of an annular process derived from the placenta or funiculus, and gradually proceeds upwards, so as to produce a more or less complete additional covering to the seed, on the outside of the testa. This arillus is well seen in the Nymphcea. But the false arillus or arillode arises from the micropyle, and seems to be a development or expansion of the exostome, which gradually extends itself more or less over the testa to which it forms a covering, and after thus coating the seed, it may be even bent back again so as to enclose the micropyle.... In the Nutmeg, the arillus originates from both the hilum and the micropyle; it forms a scarlet covering to the testa, and is commonly known in commerce when dried and preserved, under the name of mace. According to Miers, the arillode in the Spindle-tree is produced from the funiculus and not from the exostome, in which case it would necessarily be an arillus, and not an arillode as commonly described. In practical Botany both the true arillus and arillode are commonly designated under the general term of aril.” (Bentley pp.337-338).