[R] Arrangement of names

[Michael Eisenring]

Dear R-help members
I would be grateful if anyone could help me with the following problem:

1: I changed the font style of the plant names (along x-axis, under the bars)  to "italic" . How can I avoid that the font in the legend also changes to "italic"?
2. I would like to place the plant names (along x-axis, under the bars) in a way that :
a) the first plant name is under the first bar (now the first name is too much to the right). If I change the x value under "text" all names are shifted to this one x-coordinate.
b)the plant names should start all on the same "height" (e.g. all exactly on y=-6.5. Now they are misplaced

Any ideas?

Thank you very much
Michi


input data (dput):

structure(list(total = c(28L, 17L, 11L, 6L, 6L, 5L, 4L, 3L, 3L, 
2L), young = c(29L, 22L, 15L, 8L, 5L, 3L, 2L, 2L, 2L, 2L), old = c(36L, 
11L, 11L, 8L, 6L, 5L, 4L, 3L, 2L, 2L)), .Names = c("total", "young", 
"old"), class = "data.frame", row.names = c(NA, -10L))



R: Code

plants_herbs_input_top10 <- structure(list(total = c(28L, 17L, 11L, 6L, 6L, 5L, 4L, 3L, 3L,
                                                     2L), young = c(29L, 22L, 15L, 8L, 5L, 3L, 2L, 2L, 2L, 2L), old = c(36L,
                                                                                                                        11L, 11L, 8L, 6L, 5L, 4L, 3L, 2L, 2L)), .Names = c("total", "young",
                                                                                                                                                                           "old"), class = "data.frame", row.names = c(NA, -10L))

# Keep the return value, we'll need it later
# to know where to place the bars names
bp <- barplot(data.matrix(plants_herbs_input_top10),
              width = 1,
              ylim = c(0,50),
              xaxt = "n",
              space = c(0.2, 1.0),   
              ylab = "Relative frequencies (%)",
              beside = TRUE,
              col = rep(c("black", "chartreuse1", "chartreuse4"), each=10),
              cex.names = 0.8)
par(mar=c(9, 4.1, 4.1, 2.1),font=3)

#    names.arg = rep(as.character(1), 3))
text(as.vector(bp),y=-6.5, cex=0.7,labels = c("Oplismenus sp.","Isachne mauritiana","Piper capense","Asplenium aethiopicum","Psychotria sp (seedlings)","Elatostema monticolum","Landolphia buchananii","Blotiella sp.","Asplenium elliottii","Hypoestes triflora","Isachne mauritiana","Oplismenus sp","Piper capense","Landolphia buchananii","Asplenium aethiopicum","Blotiella sp.","Carex chlorosaccus","Asplenium elliottii","Asplenium friesiorum","Polystichum sp.","Oplismenus sp","Psychotria sp (seedlings)","Elatostema monticolum","Asplenium aethiopicum","Hypoestes triflora","Piper capense","Asplenium elliottii","Blotiella sp.","Isoglossa substrobilina","Polystichum sp."),srt = 50,xpd = TRUE)

legend.width <- max(strwidth(c("Total", "Young secondary forest","Old secondary forest")))

legend(23,54,
       c("Total", "Young secondary forest","Old secondary forest"),
       cex=1, pt.cex=1.7, pch=15, y.intersp=0.4,bty="n",
       text.width = legend.width/2.5,      #------> legendbox : text ratio
       col=c("black","chartreuse1","chartreuse4"))