weird species statistics of NR annotation

Question

[l0o0]

Hi, I am doing a denovo rna-seq project of Brassica alboglabra. After assembling, I blast the unigene to the NR database. Most of the unigenes have a NR annotation. So I want to summary the species counts in unigenes' NR annotation.

In this species summary, about 50% of annotations are in Arabidopsis salsuginea, less then 5% are in Brassica napus and Brassica rapa.

Which make me weird is that Brassica napus and Brassica rapa have closer genetic relationship with Brassica alboglabra. But in the summary these two species are less than Arabidopsis salsuginea.

It really makes me comfused, is there any explanations for this?

Thanks ;)