GLOSSARY 323 
thini’um (6%, 6vds, a dune), a dune formation; thinad, a dune plant. 
tiphi’um (cidos, pool), a pool formation; tiphad, a pond plant. 
tiri’um (reipw, rub away), a bad land formation; tirad, a bad land plant. 
tonobole (révos, tension), a plant whose seeds are scattered by projection 
from calyx or involucre. 
transect (¢vansectus, cut through), a cross-section of vegetation. 
trechometer (tpéyw, to run off), an instrument for measuring run-off. 
tribi’um (7pi@v, wear or rub away), a succession in an eroded soil. 
umbrinus, umber. 
variable, able to produce variants; variant, a form arising from origin by 
variation; variation, the origin of new forms by the action of selection 
upon minute differences. 
vegetation form, a characteristic plant form, e. g., tree, rosette, etc. 
vernal, pertaining to spring. : 
vicine (vicinus, neighboring), invading from adjacent formations. 
viridis, green. 
vixgregarious, arranged in small or indistinct groups. 
water-content, the water of the soil or habitat; physiological, the available 
soil water; physical, the total amount of soil water. 
xenodoche (£éévos, strange), an anomalous succession. 
xerad (énpds, dry), a xerophyte; xerasi’um (éypacia, drought), a succession 
due to drainage or drought; xeriobole (éypia, dryness), a plant whose 
seeds are scattered by dehiscence due to dryness; xerohyli/um (8Ay, 
forest), a dry forest formation; xerohylad, a dry forest plant; xerophyll, 
the leaf of a xerophyte; xerophyte, a dry soil plant; xerophyti’um, a 
xerophytic formation; xerophilous, dwelling in a dry habitat; xero= 
poi’um, a heath formation; xeropoad, a heath plant; xerosta’tic (orarttkds, 
standing), used of successions which are completed under xerophytic con- 
ditions; xerotro’pic (rpomxés, turning), applied to successions which be- 
come xerophytic. : 
zonation, that condition in which plant groups or formations appear in belts 
or zones. 
zone, a belt of more or less uniform vegetation. 
zoochore ({éov, animal), a plant distributed by animals. 
