Disk

[Lat. discus. See Disc, DISCUS, DESK.] A flat, round piece of stone or metal; a quoit. The face, or visible surface of a celestial body, as of the sun, moon, or planets. ( Bot .) A term now applied to whatever intervenes between the stamens and the ovary upon the thalamus. It presents a great variety of forms; thus, in the Orange it forms a fleshy ring, surrounding the base of the pistil; on the Tree Peony, a dark-red cup-shaped expansion, covering nearly the whole of the pistil except the stigmas; in the Rose, a sort of waxy lining to the tube of the calyx; in umbelliferous plants, a swelling on the top of the ovaries, adhering to the styles. In other cases. the D. is reduced to little separate glandular bodies, as in cruciferous plants; or in scales, as in the Vine; or to various petaloid expansions, as in the Aquilegia.