sessile, a.
(ˈsɛsaɪl, ˈsɛsɪl)
[a. L. sessilis sitting down, dwarfed, stunted, f. sess-, ppl. stem of sedēre to sit: see -ile.]
1. Having no footstalk. a. Bot. Of leaves, fruits, flowers, or other organs: Immediately attached by the base; not having a peduncle, pedicel, or the like. Hence of a species or variety (e.g. of oak) bearing sessile fruits: opposed to pedunculated.
| 1753 Chambers' Cycl. Suppl. s.v. Leaf, Sessile Leaf, one which rises immediately from the stalk without any pedicle. 1756 Phil. Trans. XLIX. 835 The leaves..[are] generally quite sessile, or close to the stalk. 1785 Martyn Rousseau's Bot. vi. (1794) 70 In the whole compound class the seed is always sessile, that is, it bears immediately upon the receptacle without any intermediate pedicle. 1861 S. Thomson Wild Fl. i. (ed. 4) 71 Seed-vessel of common Poppy, showing the rayed stigma..placed close down, or sessile upon the ovary. 1875 Lyell's Princ. Geol. II. iii. xliv. 507 Prostrate trunks of the Sessile Variety of the Common oak occur. 1879 A. Gray Struct. Bot. vi. §6. 251 The filament, being only a stalk or support, may be very short or wholly wanting; the anther is then sessile. 1882 Vines Sachs' Bot. 565 In Piperaceæ however the stigma, which is sessile on the apex of the ovary, is often placed obliquely or divided into several lobes. |
b. Zool. Of limbs or organs: Immediately in contact with the structure to which they are attached; having no connecting neck or footstalk. Also of certain animals.
| 1777 Pennant Brit. Zool. IV. 61 The shell..fixed by a stem: or sessil. 1834 M{supc}Murtrie Cuvier's Anim. Kingd. 298 The Læmodipoda are the only Malacostraca with sessile eyes. 1840 F. D. Bennett Whaling Voy. II. 248 A sessile spur on the heel. 1851 Darwin Monogr. Cirripedia i. (Ray Soc.) 4 The more important valves..being common to the pedunculated and sessile Cirripedes. 1870 Rolleston Anim. Life Introd. 65 The cerebral hemispheres always contain a lateral ventricle, which is prolonged into the interior of the sessile olfactory lobes. |
c. Path. Of morbid growths, warts, etc.: Adhering close to the surface.
| 1725 Huxham in Phil. Trans. XXXIII. 380 During the Suppuration, the Pox would become very sessile, and the coherent kind would enlarge their Bases exceedingly. 1822–29 Good's Study Med. (ed. 3) V. 670 Simple Wart, Simple and distinct: sessile or pensile. 1899 Allbutt's Syst. Med. VIII. 891 The skin..in many cases ‘peppered’ with warts, both sessile and pedunculated. |
2. Of certain animals: Sedentary, fixed to one spot; not ambulatory. Of cells: Immobile. Also in extended use.
| 1860 Wraxall Life in Sea x. 242 They [Serpulariæ, etc.] are, therefore, nothing further than sessile nurses, just as the Siphonophoræ are nurses swimming about freely. 1871 E. D. Cope Orig. Fittest (1887) 193 It is now important to observe that great numbers of centrifugal animals are sedentary or sessile; while the longitudinal are vagrant, moving from place to place. 1879 G. Allen Colour-Sense iii. 23 Sessile or sedentary animals, as a rule, do not possess any form of visual organ. 1880 E. R. Lankester Degeneration 39 We may now proceed to look at some sessile or immobile animals which are not usually regarded as degenerate. 1904 Brit. Med. Jrnl. 10 Sept. 586/1 Certain cells which are normally fixed or sessile cells. 1917 M. Webb Gone to Earth xiii. 118 People remained in a sessile state over tea for a long time. 1926 T. E. Lawrence Seven Pillars (1935) 7 The current of tribal movements..sessile or nomad. 1930 Auden Poems 56 No chattering valves of laughter emphasised Nor the swept gown ends of a gesture stirred The sessile hush. 1971 Guinness Bk. Records (ed. 18) 169/2 The longest recorded push of a normally sessile object is of 411 miles in the case of a wheeled hospital bed. |
3. Cryst. Of a dislocation in a crystal: unable to migrate through the lattice; fixed.
| 1949 F. C. Frank in Proc. Physical Soc. A. LXII. 202 Glide is prevented by a large restoring force... Such a dislocation will be called ‘sessile’, in contrast with ‘glissile’ dislocations—those which are capable of glide. 1966 C. R. Tottle Sci. Engin. Materials iv. 101 Frank described one form of sessile dislocation, in which an aggregate of vacant lattice sites collapses to form a loop of dislocation surrounding a disk of stacking fault. 1973 J. G. Tweeddale Materials Technol. I. v. 111 In the latter case they lock together (forming a sessile dislocation) and become very difficult to separate. |
4. Comb., as
sessile-eyed,
sessile-flowered,
sessile-fruited,
sessile-leaved adjs.;
sessile oak,
Quercus petræa, which has stalkless acorns;
= durmast.
| 1854 A. Adams, etc. Man. Nat. Hist. 294 *Sessile-eyed Crustaceans (Edriophthalmata). |
| 1796 C. Marshall Gardening xix. (1813) 372 Herb-true-love, nodding, and *sessile flowered. |
| 1846 Keightley Notes Virg. Flora 391 The Quercus sessiliflora, or *sessile-fruited oak. |
| 1822 Hortus Anglicus II. 356 *Sessile-leaved Eupatorium. |
| [1838 J. C. Loudon Arboretum et Fruticetum Britannicum III. 1736 (heading) The sessile-flowered Oak.] 1906 Elwes & Henry Trees Gt. Brit. II. 291 *Sessile or Durmast Oak... More regular branching, resulting in a denser crown of foliage. 1971 Country Life 23 Dec. 1772/1 The lighter soils and hills were covered by the sessile oak, with acorns pressed against the twigs, and leaves on long stalks. |
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Add: Hence
seˈssility n.| 1903 Amer. Geologist XXXI. 204 Such cases as these make cameration appear as a result of vertical sessility and therefore allow us to infer from such cameration, this sessile mode of life. 1940 Nature 30 Mar. 484/2 Altenburg..notes that hermaphroditism is related to sluggishness and sessility. 1982 Acta Biol. et Med. Germanica XLI. 145 The loss of this glycoprotein might thus be associated with a loss of sessility of bovine lymphoid cells. |