1253 



Ei)t Ercagury at 33otamn 



[ZYGO 



ZOSTER03TYLIS. Cryptostylis. 

 ZOTSIA. A genus of grasses belonging 

 to the tribe Androvogonece. The inflores- 

 cence is in simple raceme-like spikes; spike- 

 lets consisting of one sessile flower; lower 

 glumes often wanting, upper with short 

 ' awns ; pales two, membranaceous and hair- 

 ! pointed, the upper one-nerved, the lower 

 nerveless ; stamens three ; styles two. The 

 three species described are natives of the 

 East Indies and Japan. [D. M.] 



ZOZIMIA. A genus of Umbelliferm, con- 

 i taining two species of herbs, with decom- 

 pound leaves, compound umbels, and 

 manv-leaved involucres and involucels. 

 1 The calyx-limb is five-toothed ; the petals 

 ' obovate and emarginate, with an inflexed 

 apex; the hairv fruits flattened dorsally; 

 | the carpels with five ribs ; the commissure 

 with two vittas; and the carpophore 

 bipartite. [W. C] 



ZTJCCA. Under this name has been 

 mentioned, rather than described, a plant 

 of the Ciicurbitacece, with lateral tendrils, 

 and solitary axillary flowers, concealed by 

 a large bract. The calyx has five coloured 

 sepafs ; and the male flowers have five 

 stamens. Little else is known of this 

 genus. [M. T. MJ 



ZUCKER WURZEL. The German name 

 for the Skirret root. 



ZURLOA. The plant upon which this 

 genus of Meliacece was established by 

 Ten ore found its way into some of the 

 Continental gardens, but its native coun- 

 trvand history are unknown. It is an ever- 

 green tree, with unequally pinnate smooth 

 shining leaves, and large terminal pani- 

 cles of white and rose-coloured flowers, 

 which have a small five-toothed calyx, 

 five roundish or elliptical petals (the edges 

 of which meet without overlapping in the 

 bud) a ten-toothed stamen-tube with as 

 many elliptical anthers inside, and a five- 

 furrowed ovary bearing a conical style and 

 flat cup-shaped stigma. Its fruits are top- 

 shaped five-angled capsules, having five 

 single-seeded cells, and splitting open into 

 as many valves when ripe, the seeds being 

 black and as large as chestnuts. [A. S.] 



ZURRUT. An Arab name for Sorghum 

 vulgar e. 



ZYGADEXUS. A genus of Melanthacece 

 from North America. It consists of smooth 

 somewhat glaucous herbs, with cr-eeping 

 rhizomes or coated bulbs, grass-like leaves, 

 and panicles of rather large greenish-white 

 flowers, which are perfect with a withering 

 spreading perianth of six leaves, sessile or 

 slightly clawed at the base, where there are 

 one or two glands ; sometimes the bases ad- 

 here to the ovary ; stamens six ; styles 

 short subulate ; capsule tripartible at the 

 top, with six or eight margined or slight- 

 ly-winged seeds in each cell. [J. T. S.J 



ZYGIA. A genus of trees or shrubs, of 

 the Mimosece division of Leguminosce. The 

 -pp-cies are natives of Tropical America 

 and Africa, and also of the Cape of Good 



Hope. They have bipinnate leaves, and 

 flowers in panicles or in spiked heads;. 

 calyx tubular, five-toothed ; corolla funnel- 

 shaped, five-cleft ; stamens numerous, the 

 filaments combined into a spirally-twisted 

 tube, projecting far beyond the petals; 

 style longer than the stamens ; pod 

 flattened, membranous, divided by cellular 

 partitions into several compartments; 

 seeds numerous. [M. T. M.] 



ZYGNEMACEJE. A natural order of 

 greeu-spored Algce, characterised by float- 

 ing (rarely attached) jointed threads, with 

 a spiral or figured endochrome, propagated 

 by large zoospores formed from the union 

 of the two contiguous endochromesin the 

 same or neighbouring threads, or by the 

 bisection of a single endochrome. They 

 abound in fresh w 7 ater, and have been 

 much studied on account of the curious 

 structure of the endochrome, and the 

 phenomena attending the formation of 

 the zoospores. In some genera (as Zyg- 

 nema, Mougeotia, and Thwaite&ia) union 

 between contiguous threads is effected 

 either by simple contact and subsequent 

 amalgamation, or bymeans of lateral tubes. 

 The spermatozoids are either derived 

 immediately from the cells, or from 

 antheridia produced from the cells as in 

 CEdogonium, The endochrome is some- 

 times stellate, sometimes marked with a 

 line of globules or with the globules 

 symmetrically arranged, or is disposed in 

 one or more spirals. When the latter are 

 numerous, the similarity to the spiral 

 vessels of phaenogams is very striking. '; 

 CEdogonium is in several respects anoma- j 

 lous ; but though the threads are attached, j 

 and there is no union of threads, added to j 

 the peculiarities of theimpregnation.it is i 

 more readily referred here than to any 

 other order, unless a new order is proposed 

 for its reception. In Tliwaitesia and : 

 (according to Mr. Thwaites) in Mesocarjms ; 

 and Staurocurpus the mass arising from 

 the endochrome of two contiguous joints ; 

 is ultimately resolved into four zoospores, j 

 Exotic species are but little known, but 

 there is no doubt, from the example of 

 India, that they are frequent in hot as 

 well as in temperate countries. [M. J. B.] 



ZYGODESMTJS. A genus which, accord- 

 ing to the degree of condensation of 

 the creeping'threads which constitute the 

 pi-incipal mass of the fungus, may be 

 assigned with almostequa; propriety to Au- 

 ricularini and Mucedivei. The peculiar cha- 

 racteristic consists in these threads being 

 suddenly bent in such a manner, that on 

 one side there is a little swelling or 

 knuckle, and on the other an indentation 

 occupying about two-thirds of their 

 diameter, and looking like a septum, the 

 thread then resuming its original course. 

 The commonest species is Z.fuscus, which 

 occurs on sticks and decayed timber in 

 woods. Its spores are globose and rough 

 with little points. [M.J. B.] 



ZYGODONTEI. A small natural order of 

 acrocarpous mosses proposed by Dr. Mon- 



