Psilotum, more commonly known as whisk ferns due to the nature of their appearance and their use in the making of brooms in the past, is a genus of fern-like vascular plants. This "vascular" description implies that the plants that fall within this genus have conducting systems that transport nutrients and water throughout the plant, providing the necessary resources as they are required. This is very important for the life of the plant since the different parts will be provided with what is needed when required, thanks to an efficient conductive system. While the plants within this genus, particularly the two species Psilotum nudum and Psilotum complanatum, are vascular in nature like many of the plants out there, the similarities with other plants end there. Whisk ferns noticeably lack many organs that other plants tend to have. The whisk fern has no roots, leaves, flowers, fruits, or seeds, and the plant primarily consists of stems. Since these plants do not have roots, some of the stems extend below the ground in order to absorb nutrients, minerals and water. This underground stems are called rhizomes.
The distribution of Psilotum is mostly tropical and subtropical. These plants are known to be found in the New World, the Pacific, some parts of Europe and the U.S., as well as in southern Japan.
Since whisk ferns have no flowers or seeds, the plants reproduce by the spread of spores. The above ground stems of Psilotum nudum have small appendages, not unlike scales, called enations as well as clustered yellow spherical structures called synangia. These synangia produce the spores for reproduction. Spores are single-celled units that are capable of reproduction and so enable these plants are able to produce the next generation. When the synangia are mature, they open up and in doing so, release the spores. These spores are dispersed into the wind, and since they are tiny and extremely light, the spores can be carried large distances until they are able to produce the next generation.
The plants in the Psilotum genus are ancient. Evidence suggests that ancestors of these plants looked very similar to Psilotum nudum, and existed over 400 million years ago. It is unknown whether the oldest of these plants evolved from other plants or came about independently. Whisk ferns are of little scientific interest since there are so different from most of the other plants commonly found around the world today, both with respect to genetics and morphology, and so studying them is unlikely to hold much benefit to mankind.