Oyno-zoogonidioin 



Hemicycadales 



G3mo-zoogonidi'um (+ Zooooni- 

 dium), female filaments derived 

 from zoogonidia in Oedogonium 

 Link (West). 



Qyp'sophiles {gypsum, plaster of Paris), 

 plants loving chalk. 



Oyrog'onites, pi. {yvpos, round ; yovos, 

 offspring ; + ite), fossil fruits of 

 Chara Linn., at first taken to be 

 shells, " Gyroliths." 



H +, see pH ; H-i'on [hydrogen ion] 

 (tov, pt. of verb to go), a physical 

 term for acid-alkali equilibrium 

 (Duggar). H-ions are acid and 

 bear a positive electric charge ; 

 pH-ions are basic, with a negative 

 electric charge ; H-pieces, the 

 halves of neighbouring cells of 

 Tribonema Derb. et Sol. 



Hab'itat-Com'plex, cf. Edaphic For- 

 mation ; ~ Types formed from 

 parallel series of habitats (G. E. 

 Nichols). 



Hairs: Muc'ilage ~, possessed by 

 certain algae ; sheathed ~, of 

 Sphacelariaceae, the apical cell 

 dies and the cell below proliferates 

 through the cavity, leaving a basal 

 sheath (Church). 



hal'arch {apxiq, origin), saline con- 

 ditions prevailing in this succession. 



Half-sta'men (+ Stamen), in Cu- 

 cumis Linn., that stamen of the 

 three which has only one loculus 

 (Heimlich). 



Hali'on, saline scrub climax (Clements) ; 

 Ealone'reid (+ Nereid), marine 

 association of algae (Warming) ; 

 halophil'ic = halophilous ; <-- Bac- 

 teria, bacteria seated on marine 

 fishes ; Hal'Dsere (+ Sere), a hydro- 

 sere with salt contents (Clements). 



Hama'da, a stony desert. 



Haplobacter'ia, true bacteria (Conn) ; 

 haplo-biot'ic, applied to certain 

 Red Algae, as Scinaia Bivona ; 

 Haplochro'mosomes, single chromo- 

 somes, which combine into a pair 

 of myxochromosomes (Chodat) ; 

 hap'loid, add, (2) the result of a 

 single gamete such as the moss- 

 plant (Lotsy) ; Haploi'dy the state 



in question; Hap'lophyll (<^yAAov, 

 a leaf), the primitive universal leaf 

 as in Tmesipteris Bemh. and lyco- 

 pods (Benson) ; haplosteph'anons 

 {oT€(f>dvr}, diadem), having a single 

 circle of stipulodes at the base of 

 each whorl of branchlets ; haplo- 

 stich'ous {oTLKos, rank), the cortex 

 with one row of cells to each 

 branchlet or bract-cell of Charads ; 

 hap'teral* adj. from Hapteron. 



Hard'pan, a hard substratum under 

 the cultivated soil, which requires 

 to be broken up for the penetration 

 of roots. 



Har'tig Net, an intercellular growth 

 associated with a fungus mantle 

 on the roots of conifers (Frank). 



Hat, an old term for Pileus. 



Head"Cells, (1) cells at the distal end 

 of the manubrium of Characea«, 

 bearing the filaments containing 

 the antherozoids ; (2) cells on 

 exterior of node-cells of the stem- 

 cortex bearing spine-cells in certain 

 Charads. 



Heleochare'tum, shortened from 

 Heleocharite'tum, an association 

 of Heleocharis R.Br. 



Helichryse'tnm, association of Heli- 

 chrysum Vaill. 



Heli'on, changed from Heli'nm, 

 swamp scrub climax (Clements). 



beliotac'tic {tactio, touch), light per- 

 ceptivity. 



hemerodiaph'orous {-quepos, cultivated ; 

 Sia^opoc, different) ; varied under 

 cultivation (Linkola) ; hemero- 

 ph'ilous {4>iXioj, I love), readily 

 cultivated {id.); hemeroplio'bous 

 ((f>6^os, fear), hard to cultivate {id.). 



Hemiang'iosperms, cf. Proanoio- 

 sperms ; Hemibasidiomyee'tes ( + 

 Basidiomycetes) consist of the 

 Ustilaginales with an indefinite 

 number of basidiospores ; Hemi- 

 cryptophytosynu'sia, life-forms such 

 as perennial plants with buds 

 on the level of the soil, but not 

 related to each other (Gams) ; 

 Hemicycada'les, plants akin to 

 Cycas, but more or less distinct, 

 bisexual (Wieland) ; Hemihetero- 



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