Rosa venusica manticora
"Venusian Manticore Rose"
Shown above is a photostat of one of the more dangerous plants on Venus: Rosa v. manticora, or the Manticore Rose. It is so named for several features. First, it has a red coloration like the common variety of Earthly roses. Second, the odor of the blossom is quite similar to that of the common rose. However, the Manticore Rose is a single stemmed plant, unlike the thorny thicket of stems typical of the common rose. It would seem that, lacking this defense (of thick sharp thorns), the Manticore Rose would be easy prey for herbivorous creatures of the rainforest.
The truth is, most creatures avoid this plant. You see, the large bulbous blossom has the ability to fling a volley of sharpened thorns at any creature that approaches within a dozen feet or so of the plant. These thorns, beyond their sharp points, are also envenomed. While observation of larger Venusian lifeforms indicates that they may be immune or merely irritated by these toxins (as humans are to various stinging nettles), Earth creatures are rapidly overcome. The toxin puts its victim into a deep comatose state.
It is believed by the Texican scientific group's chief botanist, Doctor Nigel Clive of the Agricultural College of Texas that the plant feeds on small creatures that are overcome by the toxin and fall to the ground near the root system. These animals perish of malnourishment while comatose, and their bodies decompose, feeding nutrients in to the soil.
There is no known antidote for Manticore Rose poison. Two Texican marines are still comatose months after being poisoned. Travelers to Venus are warned that if they smell roses, they should proceed very cautiously.