Dictyogens 



Diffusion 



netted veins, proposed by Lindley as 

 intermediate between his Endogens 

 and ExoGENs; dictyog'enous, ap- 

 plied to monocotyledons with netted 

 veins ; <-' Lay'er, a layer of meristera 

 general in monocotyledons, which 

 gives rise to the central "body " and 

 cortex of the young roots (Mangin) ; 

 dictyomeriste'lic ( + Mkristele), 

 the stem -steles in certain Ferns thus 

 designated by Brebner ; Dictyospo'rae 

 (4- Spoha), Fungi having muriform 

 spores (Traverso) ; Dictyosporan'gi- 

 uitt(+ Sporangium), the sporangi- 

 um of Saprolcgnia, with encased 

 spores germinating within the spo- 

 rangium (Walpole and Huxley); 

 Dict'yostele ( + Stele) a stele with 

 large overlapping leaf-gaps ; — dis- 

 sec ted ■~', a perforated dictyostele 

 in which the strands of the stelar 

 network are reduced to thin threads 

 (Tansley); per'forated '-, a dictyo- 

 stele in which gaps other than leaf 

 gaps occur; siphon'ic ■~,when the 

 network of meristeles is simple and 

 tubular (Brebner) ; adj. dictyoste'lic ; 

 Dictyox'ylon {^v\ov, wood), applied to 

 the cortex of a fossil stem possessing a 

 netted system of hypodermal fibrous 

 strands, as in Lyginodendron (Scott). 

 Dictyu'chus State of Saprolegnieae 



(Hartog) = DiCTYOSPORANGIUM. 



dicy'clic (Sis, two ; kvkKos, a circle), 

 (1) when a series of organs is in two 

 whorls as a perianth ; (2) applied 

 to biennials ; Dioy'cly, the condition 

 of having two concentric vascular 

 cylinders ; Di'cyme, a cyme in which 

 the lirst (or higher) axes again form 

 cymes (Eichler) ; — a two-fifths 

 spiral expressed in terms of two 

 circles, two outside, and three inside 

 (Church) ; dicy'mose [nvixa, a wave), 

 doubly cymose ; didip'loid (5<, twice, 

 -f diploid), used of a nucleus con- 

 sisting of the fusion of two diploid 

 nuclei (Nemec) ; cf. syndiploid;- 

 did'romic {Sp6fxos, a course), doubly 

 twisted, as the awns in Danthofiia, 

 Stipa, etc.; Did'romy, double torsion ; 

 Didymospo'rae (-f Spoua), Fungi 

 bearing spores in pairs (Traverso). 



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did'ytnous, -its {SlSv/xos, twin), (1) found 

 in pairs, as the fruits of Umbelli- 

 ferae ; (2) divided into two lobes ; 

 '-' An^'thers, when the two lobes are 

 almost destitute of connective. 



Didyna'mia {5\s, twice ; Svvafxis, 

 power), a Linnean class marked by 

 didynamous flowers; didyna'mian, 

 didy'namous, flower, four-stamened 

 with stamens in pairs, two long, 

 two short, as in most Labiatae. 

 Didy'namy, the condition above 

 defined. 



Die-back, of Salix, a disease due to 

 Diplodina salicina ; '^ of Citms, 

 some uncertain condition of health ; 

 -- of Prunus, from Naemospora 

 crocea. 



Dientomophlly (+ Entomophily), 

 when in a species, some individuals 

 are adapted for insect- fertilization 

 by a ditierent group of visitors 

 from the remaining individuals 

 (Engler and Prantl). 



Dieres'ilis, Dieresil'ia {hiaipiu), I 

 divide), Mirbel's name for Car- 

 CERULE ; adj. dieresirian. 



Diete'siae (5<, two ; ir^aios, annual), 

 perennials with short shoots, long 

 shoots being absent or fugacious 

 (Krause). 



Differentia'tion, of a Cell-wall, the 

 arising of apparent layers ; '^ of 

 Tis'sues, their development into 

 permanent tissue and consequent 

 diverse growth. 



diffluent {diffluens, dissolving), having 

 the power to dissolve, or readily 

 doing so. 



^iSLormedJ ,difforin'is {dis-, apart ;/orma, 

 shape), of unusual formation or 

 shape ; Difform'itas (Lat.), an 

 abnormality. 



diffract', diffrac'tus (Lat., broken), 

 broken into areolae separated by 

 chinks. 



diffuse', diffu'sus (Lat., spread abroad), 

 wide y or loosely spreading ; '^ 

 Col'our, a colour which has "run" 

 into the surrounding tissues ; 

 Diffu'sion, (1) tei-m used by Wiesner 

 for the intermingling of different 

 gases under equal pressure, with or 



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