Exochite 



Expansion 



ing of MESISTEM "thickening ring" 

 and PERISTEM, young cortex ; it is 

 the tissue of protomeristem which 

 is not young pith. 



Ex'ochite (ew, outside, x 17 ^* a tunic), 

 the outermost membrane of the egg 

 in Fucaceae (Farmer) ; Exocor'tex, 

 (cortex, bark), a special triple layer 

 in the roots of saprophytic Orchids ; 

 Exoderm'is (5e/>/ui, skin), the outer- 

 most cortical layer of the adult 

 root, answering to the hypoderma 

 of the stem. 



Excoe'mum (e, out, ofywiw, I issue), 

 a fringe or tuft of hair at the base 

 of the glumes in some grasses 

 (Richard) ; exocatad'romous ( + 

 CATADROMOUS), when Ferns in their 

 nervation have their stronger 

 pinnules anadromous, and their 

 weaker catadromous ( Prantl ) ; 

 Exog'amy (ya/ios, marriage), the 

 tendency of closely allied gametes to 

 avoid pairing ; exog'enous exog'enus 

 (yevvdu, I bring forth), (1) growing 

 as the wood of Dicotyledons ; (2) 

 arising from superficial tissue ; 

 Ex'ogeus, Exog'enae, plants which 

 increase in growth by the addition of 

 wood on the outside beneath the 

 constantly widening bark ; Exog'y- 

 nous, exog'ynus (7^77, woman), where 

 the style is exserted beyond the 

 flower ; Exoisog'amy ( + ISOGAMY), 

 when a gamete will pair only 

 with a similar gamete of another 

 brood (Hartog) ; exonas'tic (JXKTTOS, 

 pressed close), in anatropous or 

 campylotropous ovules when the 

 curvature is horizontal towards 

 the median nerve of the side of 

 the upper face of the carpel 

 (Van Tieghem) ; cf. ENDONASTIC ; 

 Exoneuro'sis (vetpov, a nerve), the 

 separation of veins in appendicular 

 organs, and their reappearance as 

 teeth, spines, or bristles, as in the 

 Barberry (Clos) ; Exoperid'ium ( + 

 PERIDIUM), the outer layer of the 

 peridium of such Fungi as Ly coper- 

 don, which peels or flakes off on 

 maturity ; exophyll'ous -us (<j>v\\ov, 

 a leaf),* not having a foliaceous 



sheath, with naked cotyledons : 

 exop'tile, exop'tilis (TTT&OV, a 

 wing) = EXOPHYLLOUS, said of 

 an embryo whose plumule is naked 

 upon, or between cotyledons and 

 not rolled up in one (Lindley) ; 

 Exorhi'zae (pifa, a root), = EXOGENS ; 

 exorhi'zal, exorhiza'lis, the radicle 

 not sheathed, so the primary root 

 in germination has no covering to 

 pierce; Exos'mose , Exosmo'sis(w/j,6s, 

 a thrusting), the passage through a 

 membrane outwards from a thin to 

 a dense fluid ; Exosclero'tes (<r/cXi7p6s, 

 hard), sclerotia which are external 

 to the surface of Agarics ; Ex'- 

 ospore, Exospor'ium (<riropd, seed), 



(1) the outer covering of the spore ; 



(2) a thick coat developed from the 

 periplasm round the odspore in 

 Peronosporeae ; exos'porous, hav- 

 ing scattered spores, as Fungi ; Ex'- 

 ostome, Exost'oma (oro/ia, a mouth), 

 the foramen of the outer coat of the 

 ovule ; Exosto'sis (6<rTeov, bone), 

 (1) the nodules on roots of Legumi- 

 nosae ; (2) the hard turgescence of 

 sound wood, showing as prominent 

 knots ; Exosty'lus $ ( + STYLUS), 

 Mirbel's word for fruit as in 

 Labiatae, four seemingly naked nut- 

 lets ; Exotne'cium (#77*77, a case), (1) 

 the outer case of the anther 

 (Henslow, Lindley) ; (2) Purkinje's 

 term for the extine or outer 

 layer of pollen-grains. 



exoteric (e|wre/ot:os, external), aris- 

 ing from outside the organism, the 

 opposite of ESOTERIC. 



exot'ic (ea>riKos, foreign), not native, 

 introduced from abroad ; Exot'ics 

 are those plants which are not in- 

 digenous. 



exotroph'ic (ew, out of,r/>o077,nourish- 

 ment), employed by Wiesner where 

 an organ or lateral shoot, as op- 

 posed to the mother-shoot, is most 

 strongly developed ; Exot'rophy, 

 development of lateral shoots 

 instead of the main axis. 



expand'ed, expan'sus (Lat. spread 

 out), diffuse ; Expansion, the con- 

 dition of a flower in full perfection j 



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