either things went much worse, or those were not white ones. anyway, 3 rhinos left means species is extinct, unless mighty genetics step in in near future.
The southern [0] has one horn and there are an estimate of 20,400+ alive in the wild. Although they are still quite rare, they are considered the most common and widespread rhino.
The northern [1] white rhino is the one mentioned in this article and is much, much more rare. There are now only three individuals alive. I haven't found any confirmation, but I thought the northern was more popular by poachers because of the two large sized horns, instead of a large and small one from the southern rhino.
All in all, very sad we came to the point human beings have (almost, for now) killed yet another species.
There are 224 different mammals so far, but no rhinos.
For plants, the Millennium Seed Bank [2] is collecting and storing seeds with the aim to have all species. They have 13% of plant species so far.
[1] http://www.dnabank-network.org/
[2] http://www.kew.org/science-conservation/collections/millenni... (my previous employer; they're recruiting for Linux analysts at the moment).