GLOSSARY 321 



ponti'um (ttcvto;, deep sea), a deep sea formation. 



potami'um (Trora/xo;, river), a river formation; potamad, a river plant. 



potometer (ttotov, drink), an instrument for measuring absorption. 



prevernal, pertaining to early spring. 



prior, earlier, used of alpine aspects. 



prochosi'um (Tr/ac'^wo-u, a deposition of mud), a succession in an alluvial soil. 



prodophyti'um (TrpooSos, pioneer), an initial formation. 



protodoche (Tr/awros, first), a primary succession. 



proximity {proximitas, nearness), nearness to the area invaded. 



psamathi'um (\}/diJxi6o<i, sand of the seashore), a strand formation; psamathad, 



a strand plant; psammo^enous (il/dixfjio<:, sand), producing a sandy soil. 

 psili'um (ij/LXd, land wichout trees), a prairie formation; psilad, a prairie 



plant. 

 psychrometer (i/^v;(pos, chill), an instrument that measures humidity by means 



of a fall in temperature; psychrograph, a psychrometer that records 



automatically. 

 ptenophyti'uin (ttti/vg's, passing), an intermediate formation. 

 pterospore (Trrepov, wing), a plant with winged disseminules. 

 purpureas, purple. 



pycnophyti'um (ttvkvos, thick), a closed formation. 

 pyri'um {Tvvp, fire), a burn succession. 



quadrat (^quadratum, a square), a square meter of vegetation marked off for 

 counting, mapping, etc.; major, a quadrat of 2-14 square meters. 



reaction, the effect of the formation upon the habitat. 



relict {relidus, left), a species belonging properly to an earlier type of succes- 

 sion than the one in which it is found. 



repium (peVw, sink), a succession due to subsidence. 



rhoi'um (poos, stream), a creek formation; rhoad, a creek plant. 



rhoptometer (/Sotttov, something absorbed), an instrument to measure absorp- 

 tion of water by the soil. 



rhyaci'um (pua|, aKos, mountain torrent), a torrent formation; rhyacad, a 

 torrent plant. 



rhysi'um (pvo-i's, a flowing of fire), a succession due to volcanic action. 



ruber, red. 



saccospore (o-a/cKos, sack), a plant with sack-like disseminules. 



sarcospore {adp^, o-apKos, fiesh), a plant with fleshy disseminules. 



sciad ((TKid, shade), a sciophyte; sciophyll, the leaf of a shade plant; sclo- 



phyte, a shade plant; sciophyti'um, a shade plant formation; sciopliii- 



ous, shade-loving. 



