options ps=60 ls=80 pageno=1 formdlim='_';

data seedlings;
input height fert $ green $;
cards;
47 f1 g1
43 f1 g1
46 f1 g2
40 f1 g2
62 f2 g1
68 f2 g1
67 f2 g2
71 f2 g2
41 f3 g1
39 f3 g1
42 f3 g2
46 f3 g2
;

/* SS(fert*green) gives us SS(E) in this setting. Note the use of the error term
in both the test and lsmeans statements. */

proc glm;
class fert green;
model height = fert green fert*green;
test h=fert green e=fert*green;
lsmeans fert/pdiff cl adjust=tukey e=fert*green;
run;