层次聚类树形图中响应变量的可视化

我想在层次聚类树图中表示响应变量“sepal.length”、“sepal.width”、“patal.length”和“patal.width”,但没有成功。我做:

#Example with iris data set
library(vegan)
data(iris)
names(iris)
# [1] "Sepal.Length" "Sepal.Width"  "Petal.Length" "Petal.Width"  "Species"  

y <- as.matrix(iris[,-5])[6*(1:25),]   # subsample to make the graphs
rownames(y) <- iris$Species[6*(1:25)]  # pretty

#Calculate distance matrix using Bray
comm.pat.dist <- vegdist(y, method = "bray")

#Create a cluter using hclust 
comm.bc.clust <- hclust(comm.pat.dist, method = "ward.D2")

# Plot cluster 
hpat <- as.dendrogram(comm.bc.clust)
nodePar <- list(lab.cex = 0.6, pch = c(NA, 19), 
                cex = 0.7, col = "blue")
plot(hpat, ylab = "Bray dissimilarity", 
nodePar = nodePar, cex=0.75, edgePar = list(col = 2:3, lwd = 2:1), horiz = TRUE)
#

现在我不知道在树图的节点中表示变量“sepal.length”、“sepal.width”、“patal.length”和“patal.width”的代码有什么变化。有人能帮我吗? 谢谢