diff --git a/pkgs/plai/scribblings/collector2.scrbl b/pkgs/plai/scribblings/collector2.scrbl
index 6cf5f5c20c..31b71141ef 100644
--- a/pkgs/plai/scribblings/collector2.scrbl
+++ b/pkgs/plai/scribblings/collector2.scrbl
@@ -70,7 +70,7 @@ Determines if @racket[v] is a root.
 
 @defproc[(heap-value? [v any/c]) boolean?]{
   A value that may be stored on the heap. Roughly corresponds to the contract
-  @racket[(or/c boolean? number? procedure? symbol? empty?)].
+  @racket[(or/c boolean? number? symbol? empty?)].
 }
 
 
@@ -185,11 +185,6 @@ store a tag, etc. You are also welcome to pre-allocate common constants (e.g.,
 the empty list). This procedure may need to perform a garbage-collection. If
 there is still insufficient space, it should signal an error.
 
-Note that closures are flat values. The environment of a closure is internally
-managed, but contains references to values on the heap. Therefore, during
-garbage collection, the environment of reachable closures must be updated. The
-language exposes the environment via the @racket[procedure-roots] function.
-
 }
 
 @defproc[(gc:cons (first root?) (rest root?)) location?]{
diff --git a/pkgs/plai/scribblings/mutator2.scrbl b/pkgs/plai/scribblings/mutator2.scrbl
index 5cd32030f7..92c3e3d82e 100644
--- a/pkgs/plai/scribblings/mutator2.scrbl
+++ b/pkgs/plai/scribblings/mutator2.scrbl
@@ -13,14 +13,13 @@
                               exact-positive-integer?)
                      (only-in racket/contract/base
                               or/c listof any/c)
-                     (only-in plai/collector
+                     (only-in plai/gc2/collector
                               root?
                               heap-size
                               location?
                               heap-value?
                               heap-set! heap-ref with-heap
-                              get-root-set read-root set-root!
-                              procedure-roots)
+                              get-root-set read-root set-root!)
                      plai/scribblings/fake-collector2
                      plai/scribblings/fake-mutator2
                      plai/random-mutator
@@ -33,12 +32,13 @@
 
 @defmodulelang[plai/gc2/mutator]
 
-The @MUTATE-LANG language is used to test garbage collectors written with the
-@secref["collector"] language.  Since collectors support a subset of Racket's
-values, the @MUTATE-LANG language supports a subset of procedures and syntax.
-In addition, many procedures that can be written in the mutator are omitted as
-they make good test cases.  Therefore, the mutator language provides only
-primitive procedures, such as @racket[+], @racket[cons], etc.
+The @MUTATE-LANG language is used to test garbage collectors written
+with the @secref["gc2-collector"] language.  Since collectors support
+a subset of Racket's values, the @MUTATE-LANG language supports a
+subset of procedures and syntax.  In addition, many procedures that
+can be written in the mutator are omitted as they make good test
+cases.  Therefore, the mutator language provides only primitive
+procedures, such as @racket[+], @racket[cons], etc.
 
 @section{Building Mutators for GC2}