You'd think at least 184 million years of evolution on entirely separate continents would be enough to make two species of fish sexually incompatible. That was the assumption scientists in Hungary were going on when they placed sperm from an American paddlefish near eggs from a Russian sturgeon in the lab.

(CNN) -- Around the world, fireflies light up the night with their shimmering bodies. But scientists say this magical display is under threat -- with the loss of their natural habitats, pesticide use and artificial light putting some of the 2,000 or so species at risk of extinction.

Adeniums have been, till recently, comparatively rare and high value succulents. In part this was because they are somewhat difficult and slow under cool conditions and in part due to the need for cross pollination to set seed. The rather complex floral structure means than hand pollination technique is not obvious.

Did you know there are more than 20,000 types of orchids in the world? That's more than four times the number of mammal species! While most are found in tropical rainforests and grasslands in far off places, a fair amount are also native to the United States.

For a few weeks each spring, a lone guard monitors the moors of northern England. This warden pitches a tent in a remote field to watch over a prize so rare that collectors have been known to break laws, trek into deep jungles, and risk capture by guerillas in its pursuit.