color vectors other than gray()

I'm trying to create a graph where different cells of a grid (a  
shapefile)
will be painted with a color share scale, where the most easy way is  
to use
gray().

Can I somehow get a vector (gradient) of colors, a vector of colors  
with
other methods but gray()?

I'm doing this until now



 quad_N_sp <-
merge(sp_dist[sp_dist 
$sp==splist[i],],grelha_ID,by.x="quad",by.y="quadricula
",all.y=T,)

 quad_N_sp$x[is.na(quad_N_sp$x)] <- 0

 quad_N_sp <- quad_N_sp[order(quad_N_sp$id),]

 paleta <- gray(1-(quad_N_sp$x)/max(quad_N_sp$x)) #! Tons de cinzento

 win.graph(4,5)

 plot(grelha,ol="grey80", #! Gr?fico com grelha de amostragem e  
gradiente
de abund?ncia

 fg=paleta,

 cex.lab=0.7,

 cex.axis=0.7,

 cex.main=0.7,

 xlab="Coord X",

 ylab="Coord Y",

 main=paste("Esp?cie: ",splist[i]),

 xlim=c(210000,240000)

 )

 col_lab <- c(max(quad_N_sp$x),min(quad_N_sp$x)) #! Vector com os  
limites
min e max do N de indiv?duos observados


color 
.legend 
(248000,120000,250000,128000,col_lab,sort(unique(paleta)),gradie
nt="y",cex=0.6)#! Legenda

 text(245300,130500,"N? Indiv?duos",cex=0.6)

 plot(blocos,ol="grey40",fg=NA,add=T)



I'd like to replace the grey shade by other colors.



Thanks in advance