, ▁including ▁also ▁dead ▁trees , ▁her b ace ous ▁plants , ▁m ush rooms , ▁and ▁tree ▁seed lings . ▁ ▁M oss ▁layer ▁G row ing ▁on ▁the ▁surface ▁of ▁the ▁forest ▁floor ▁is ▁veget ation ▁of ▁up ▁to ▁about ▁ 0 . 1 5 ▁metres ▁in ▁height ▁in ▁what ▁is ▁various ly ▁described ▁as ▁a ▁m oss , ▁soil ▁or ▁crypt og am ▁layer . ▁The ▁ground ▁itself ▁is ▁covered ▁by ▁a ▁layer ▁of ▁dead ▁plant ▁and ▁animal ▁material . ▁In ▁this ▁layer ▁and ▁the ▁underlying ▁few ▁cent imet res ▁of ▁the ▁to ps o il ▁live ▁in numerable ▁small ▁soil ▁organ isms ▁such ▁as ▁b acter ia , ▁fung i , ▁alg ae ▁and ▁micro organ isms , ▁which ▁break ▁down ▁the ▁dead ▁organ ic ▁subst ances ▁and ▁work ▁them ▁into ▁the ▁soil . ▁In ▁places ▁the ▁ground ▁is ▁covered ▁by ▁l ich ens ▁and ▁m oss es . ▁ ▁Root ▁layer ▁Also ▁known ▁as ▁the ▁rh iz os phere , ▁the ▁under ground ▁area ▁of ▁a ▁plant ▁habitat ▁is ▁the ▁root ▁layer . ▁It ▁consists ▁of ▁the ▁plants ' ▁roots ▁and ▁related ▁elements ▁such ▁as ▁rh iz om es , ▁bul bs ▁and ▁tub ers . ▁ ▁See ▁also ▁▁ ▁Rain for est ▁ ▁References ▁ ▁Bibli ography ▁ ▁H . ▁D iers ch ke : ▁plants so zi ologie . ▁Ul mer , ▁Stuttgart , ▁ 1 9 9 4 . ▁▁ ▁C . ▁S . ▁El ton : ▁Animal ▁E col ogy . ▁Sid g wick