34 ENGLISH 
Th ting ti tissue that is capable of surviving adverse conditions and later 
resuming meristematic activity; e.g., tubers of Conocephalum [f993, g1028, s1085]. 
714 perfect — a complete peristome, generally applied to diplolepidous peristomes with an 
] having both segments and cilia (see bryoid) [f710, g1074, s856]. 
T15 perforate — pierced through [f721, g241, s857]. 
716 perianth — organ of foliar origin enclosing the archegonia in most leafy liverworts [f722, 
742, s858]. 
7T1 perichaetial leaf — modified leaf or underleaf (bract; bracteole) associated with the 
gynoecium; collectively forming the perichaetium [f406, g743, $629]. 
778 perichaetium (pl. perichaetia) — the gynoecium; strictly the ensheathing cluster of 
modified leaves or underleaves (bracts; bracteoles) and perianth, if present, enclosing the 
archegonia; archaic term for the vaginula in mosses and the perianth in liverworts [f723, 
779 periclinal —- a plane of division parallel to the surface; applied to a cell division that is 
parallel to a structure; e.g., the free surface of an apical cell, merophyte or the long axis 
of a stem (opposed to anticlinal) [(724, g748, s859]. 
780 perigonial leaf — modified leaf or underleaf (bract; bracteole) associated with the 
androecium; collectively forming the perigonium [f407, g745, s628]. 
781 perigonium (pl. perigonia) — the androecium; strictly the cluster of modified leaves or 
underleaves (bracts; bracteoles) enclosing the antheridia [f725, g746, s862]. 
782 perigynium (pl. perigynia) — a somewhat fleshy, tubular structure around the archegonial 
cluster and subsequent sporophyte, derived from axial cells peripheral to the archegonial 
cluster; a perigynium may or may not be associated with a shoot calyptra; e.g., the hollow 
perigynium of Isotachis [f727, g747, s860]. 
783 perine — an extraneous deposit of remnant endothecial debris deposited on the exine of a 
spore [f728, g749, s863]. 
784 peristome — a circular structure, generally divided into 2" (i.e., 4, 8, 16, 32, or 64) teeth, 
arranged in a single or double (rarely multiple) row around the mouth of a capsule; (see 
endostome, exostome, prostome; also teeth, inner, outer, single and double peristome) 
[f729, g750, s865]. 
785 peristomial formul 
^2 decerintix E 
. "nóng ptive equation listing the peristomal number from the OPL 
" " Vis indicating relative degree of wall thickenings, any lateral displacement of the 
and prostomial development; e.g. the equation for Funaria hygrometrica is 4' /2/4z 
[f425, g751, s526]. 1 ygro 
vh t sglieseqi asi description in terms of the number of cell columns in 
nb M SM IA DRM lj ^ i istome) [f654, 
8753, s788]. p yers, per 45? arc (one-eighth peristome) [ 
787 peristomial 
arthrod. de 
cylinder — the three innermost layers of amphithecial tissue in the 
peristomial layer is proxi à e the peristome. The innermost or inner 
layers represent " poe continuous with the outer spore sac; the middle and outer 
788 persistent — not esce and outer peristomial layers, respectivelly [f264, g754, s226]. 
S 8 or non-deciduous, long lasting: e.g. tra; protonema of 
789 Ephemerum (1734, g167, s870]. ng lasting; e.g., some calyptra; p 
790 petrophilous - 'ting rocks [f735, 8756, s1021]. 
— preferring rocks [f736, g757, s871]. 
