petaloid, a.
(ˈpɛtəlɔɪd)
[ad. mod.L. petaloideus, f. Gr. πέταλον, L. petal-um petal n.: see -oid: in mod.F. pétaloïde.]
1. Bot. Of the form of, or resembling, a petal: applied to parts or appendages of the flower when ‘coloured’ (i.e. not green) and of thin expanded form and delicate texture, like an ordinary petal.
| 1730 Stack in Phil. Trans. XXXVI. 463 Where the Tube expanded itself, it divided into more than forty petaloid Segments. 1845 Lindley Sch. Bot. iv. (1858) 25 Flowers unsymmetrical, with 2 petaloid and 3 herbaceous sepals. 1875 Bennett & Dyer tr. Sachs' Bot. 470 The contrast of structure referred to is frequently wanting, both whorls being either sepaloid, as in Juncaceæ, or both petaloid, as in Lilium; in Helleborus, Aconitum, and some other species, the outer whorl or calyx alone is petaloid, the inner whorl or corolla being transformed into nectaries. 1882 G. Allen in Nature 27 July 300/2 All stamens show a great tendency easily to become petaloid. |
b. Belonging to the Petaloideæ, a division of Monocotyledons having normally flowers with ordinary coloured petals or petaloid parts, as lilies, orchids, etc. (not spadiceous, as arums, nor glumaceous, as grasses and sedges).
| 1836 Penny Cycl. V. 248 Under the name of Asphodels he [Lobel] grouped the principal part of modern petaloid monocotyledons. 1872 Oliver Elem. Bot. i. v. 58 Monocotyledons..with a perianth of petal-like leaves, hence called..Petaloid (Petaloideæ). |
2. Zool. Applied to the ambulacra of certain Echinoids, which have a dilated portion and a tapering extremity, suggesting petals of a flower.
| 1862 Dana Elem. Geol. 160 As this portion has..some resemblance to the petals of a flower, the ambulacra are then said to be petaloid. 1888 Rolleston & Jackson Anim. Life 558 Fascioles surrounding the petaloid ambulacra. |
So petaˈloidal a. (in quot. = sense 2); petaˈloideous a. = sense 1 b.
| 1872 Nicholson Palæont. 109 Ambulacra composed of simple pores, not petaloidal. |