zoll] 



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.252 



the points. The scales of the involucre 

 are ovate oblong, membranaceous at the 

 edges ; corollas ligulate ; fruits cylindrical, 

 slightly striated, provided at the base with 

 four little horns, bent downwards ; pappus 

 soft, hairy, in many rows. [M. T. M.] 



ZOLLINGERIA. A genus of Composite, 

 nearly allied to Artemisia, but distin- 

 guished therefrom by the fruits, which 

 are ovate, with a short stout beak. Z. 

 scandens is a Japanese shrub. [M. T. MJ 



ZONARIA. A genus of dark-spored 

 Algce belonging to the natural order Dic- 

 tyotacece, with fan-shaped vertically-cleft 

 fronds, and roundish scattered spots of 

 spores. The root is coated with woolly 

 hairs. The frond is opaque, and not dis- 

 tinctly zoned as in Padina, but only ob- 

 scurely marked. Under a lens, says Dr. 

 Harvey, the surface appears to be finely 

 striated longitudinally, an appearance 

 caused by the superficial cellules which are 

 ranged in lines proceeding from the base, 

 slightly diverging from one another, and 

 admitting the introduction of new series 

 of cells between each ■ original row as the 

 frond advances in growth. The genus is 

 essentially one of warm countries. We 

 have in Great Britain only Z. parvula, a 

 doubtful Zonaria, and Z. collar is, some- 

 times washed ashore in Jersey. [M. J. B.] 



ZONA.TE, ZONED. Marked with concen- 

 tric bands of colour. 



ZOOCARPS, ZOOSPERMATA. The loco- 

 motive spores of some confervas. 



ZOOSPORES. A name given to the 

 active spores of Algce, belonging both to 

 the green and dark-spored series. Their 

 activity depends either on a general coat 

 of short cilia on a circle at one extremity, 

 or on two or more lash-like cilia vari- 

 ously disposed. The occurrence of spores 

 endowed with apparently voluntary motion 

 was formerly considered so surprising, that 

 it was either rejected as unworthy of 

 credit, or the organisms which produced 

 them were considered as animals. It is 

 now, however, generally allowed that 

 there is no essential difference between 

 animal and vegetable life, and that there- 

 fore the usual indications of either are not 

 to be regarded as decisive of the especial 

 kingdom to which a being belongs in 

 which they are manifested. Zoospores so 

 long as they are free have indeed a great 

 likeness to Infusoria, but as soon as they 

 have found a fit resting-place all traces of 

 motion cease, and their offspring comports 

 itself as a vegetable. Zoospores occur both 

 in the dark and green-spored series of Algce, 

 and if Saprolegnia be fungoid, they occur 

 also among Fungi. The peculiar zoosporic 

 J sporelings of the myxogastric Fungi, con- 

 sisting, as it is said, of the animal substance 

 called sarcode which exists in similar 

 Infusoria, have been noticed. [M. J. B.] 



ZOOSPORIC. Having the characters of 

 zoospores. 

 ZOPILOTL. A Mexican cosmetic pre- 



pared from the seeds of Swietenia Mahagoni 

 mixed with oil. 



ZORILLE. (Fr.) Gompholobium. 



ZORZOLINA. An Italiun name for 

 Sesame-seed. 



ZOSTERACExE. A small order of mono- 

 cotyledons, or a tribe of Naiadacece, consist- 

 ing of marine plants resembling seaweeds 

 and living among them, but bearing long 

 grass-like sheathing leaves, and perfect 

 flowers. These latter are enclosed in the 

 sheathing bases of the leaves, have no peri- 

 anth, and are always unisexual, the sessile 

 anthers and ovaries mixed in the same 

 sheath or separated in different ones. The 

 ovary has a single pendulous ovule, and 

 terminates in a cleft style. The seed is 

 remarkable for the very large two-lobed 

 radicle folded over a highly-developed 

 plumule. These plants are found abun- 

 dantly in the seas which border Europe, 

 Asia, and North Africa, and also in the 

 West Indies and Australia. They consist 

 of the genus Zostcra, and four or five small 

 ones separated from it. 



ZOSTERA. In consequence of their ex- 

 tremely low organisation, this genus and 

 its allies have been separated from Naiada- 

 cece, to which many botanists have referred 

 them, and formed into an order— Zostera- 

 cece. Several species have from time to 

 time been described, but a few of them 

 have since been referred to other genera, 

 and the rest reduced to two. These are 

 marine herbs, usually growing in shallow 

 water near the edges of the sea, their long 

 rooting stems creeping along in the sand 

 or mud, and sending up slender erect 

 branches, bearing long narrow grass-like 

 alternate leaves, sometimes forming such 

 dense masses as to impede the passage of 

 boats. Their flowers are of separate sexes, 

 either upon the same or different plants ; 

 and are arranged in two rows on one side 

 of a leaf-like stalk, which is enclosed in a 

 sheath formed of the enlarged base of 

 short leaves, differing only in length from 

 the ordinary leaves. They have neither 

 calyx nor corolla: the males consisting of 

 a single stalkless anther, containing con- 

 ferva-like pollen ; and the females of an 

 egg-shaped one-celled ovary, containing a 

 solitary ovule, and tapering into a slender 

 style bearing two long stigmas. Both 

 species are indigenous to Britain, but are 

 also found in most other parts of the 

 world, from Iceland southward to the 

 Cape of Good Hope, Tasmania, and New 

 Zealand. 



Z. marina, the common Seawrack, 

 Grass-wrack, or Grass-weed, has leaves 

 varying from one to several feet in 

 length, and rarely more than a quarter of 

 an inch broad. These are commonly used 

 for packing, and by upholsterers for stuff- 

 ing mattresses and cushions, being sold 

 for that purpose under the names of Ulva 

 marina or Alva marina. They contain a 

 small amount of iodine, and a considerable 

 quantity of potash. [A. S.] 



