Online Trick

..The dismo package is awesome: with some short lines of code you can read & map species distribution data from GBIF (the global biodiversity information facility) easily:

library(dismo)

# get GBIF data with function:
myrger <- gbif("Myricaria", "germanica", geo = T)

# check:
str(myrger)

# plot occurrences:
library(maptools)
data(wrld_simpl)
plot(wrld_simpl, col = "light yellow", axes = T)
points(myrger$lon, myrger$lat, col = "red", cex = 0.5)
text(-140, -50, "MYRICARIA\nGERMANICA")

Here's an example of how to easily produce real nice distribution maps from GBIF-data in R with package maps...

# go to gbif and download a csv file with the species you 
# want (example data)
# ..in R first set working directory to your download directory..
data <- read.csv("occurrence-search-1316347695527.CSV",
        header = T, sep = ",")

str(data)
require(maps)
pdf("myr_germ.pdf")
map("world", resolution = 75)
points(data$Longitude, data$Latitude, col = 2, cex = 0.05)
text(-140, -50, "MYRICARIA\nGERMANICA")
dev.off()

# that's all there is to it..