ENGLISH 29 
midway between costa and margin (see mid-leaf) [f610, g662, s741]. 
656 median line — longitudinal line found on the MaMER- of a peristome tooth, that may occur 
on either or both surfaces, usually zig-zag and d in a furrow. The line 
represents the contiguous anticlinal walls of two cell columns from one of the layers of 
the peristomial cylinder (see divisural line) [f584, g676, 718]. 
657 medulla (pl. medullae) — in liverworts used to denote the internal stem and seta tissue 
when the term cortex is used for the epidermis cf. cortex) [f611, g659, s742]. 
658 meristem -- a permanent (open system) or temporary (closed system) zone of actively 
dividing, undifferentiated cells; mature tissues develop from the differentiation of cells 
generated by mitotic divisions in this zone [f614, g664, s743]. 
659 meristematic -- pertaining to or having the igit of a meristem; e.g., the intercalary 
meristematic tissue of a moss seta [f613, g665, ]. 
660 merophyte — part of a plant; applied to a aru cut or divided from the apical cell and 
all tissues and organs derived from it by subsequent division; e.g., a segment or initial 
merophyte that forms leaf, epidermal and cortex initials will form a mature merophyte 
consisting of one leaf and associated stem tissue; a plant is composed of innumerable 
merophytes [f894, g666, s745]. 
661 mesic — noit; j neither very wet nor very dry; referring to habitat [f615, g667, s746]. 
662 teniolae [f616, g668, s748]. 
663 mesohydric - — being intermediate between endo- and exohydric [f617, g669, 749]. 
664 mesophytic — adapted to a moderately humid habitat [f618, g670, s747]. 
665 mesotrophic — more or less neutral in reaction; neither acid nor basic (see eutrophic and 
oligotrophic) [f619, g221, 671, 750] 
micrometer — a microscopic unit of measurement; one-thousandth of a millimeter 
(abbreviated um) [f620, g673, s753]. 
667 micronema (pl. micronemata) -- small, thin, sparsely branched rhizoids produced on stem 
between leaves (opposed to macronema) [f621, g675, s754]. 
668 micron — older term for micrometer jme E die 
669 microphyllous -- small-leaved produce smaller than normal 
leaves (cf. flagelliform) pies g572, s752]. 
670 microstomous — having a small capsule mouth [f623, g576, s755]. 
671 midrib — a mid-vein or single costa of a leaf or thallus [f648, g677, 851, s781]. 
672 mid-leaf —- middle third of a leaf; between the upper leaf and lower leaf; referring to 
median leaf cells between the margin and costa (mid-lamina) [f1094, g159, s216]. 
673 minute — very small, inconspicuous [f624, g1089, s344]. 
674 mitrate (mitriform) -- conic and undivided (similar to a bishop's mitre) or equally lobed 
at base, referring to calyptrae (opposed to cucullate, see campanulate); e.g., Grimmia, 
Ptychomitrium £625, g688, s756]. 
675 moniliform -- like a string of beads [f628, g755, s757]. 
676 monoicous -- bisexual; with antheridia and archegonia on the same plant, including 
autoicous, synoicous, paroicous, and polyoicous (opposed to dioicous; monoecious, see 
note after autoicous) [f626, 678, s758]. 
677 monolete — having a single, linear scar on the surface that marks the point of attachment 
in the tetrad; e.g., spores of Funaria hygrometrica and Bryum caespiticium (cf. trilete) 
[f627, g679, $759]. 
