![]() ![]() ![]() Type II, Diphasiastrum complanatum (L.) Holub ( Lycopodium complanatum L.) Type III, Huperzia selago (L.) Bernh. Bruchmann ( 1898) described five structural types of club moss gametophytes, all named by a representative species: Type I, Lycopodium clavatum L. The first discoveries of gametophytes (Fankhauser, 1873 Goebel, 1887) provided us with primary knowledge about their plastic forms, which contrasts with the much more constant characteristics of the club moss sporophytes (Bower, 1894). Free‐living gametophytes are known from Devonian Period terrestrial habitats preserved in the Rhynie chert (Taylor et al., 2005). Their life cycle consists of two separate generations: gametophytes ( n) and sporophytes (2 n). Lycophyta represent the oldest extant land plants, with the earliest globally distributed fossils dating back to the Devonian Period (Wikström and Kenrick, 2001). In our review, we combine our knowledge with data available in the literature and discuss the following questions using a methodical approach: (1) How can we locate a subterranean club moss gametophyte population? (2) How can we extract the gametophytes? and (3) What new knowledge about club moss population development can be gained by analyzing juvenile club moss populations? Almost all researchers who have previously located subterranean club moss gametophytes declared that their first find was due to luck and that subsequently the researcher's intuition plays the most important role however, intuition and good luck are not scientific methods. To date, the gametophytes of most club moss species remain undiscovered in nature and are not scientifically documented. Researchers often fail to find juvenile club moss populations and thus do not discover subterranean long‐lived achlorophyllous gametophytes. ![]() The gametophytes are responsible for not only sexual reproduction, but also the determination of recruitment of the new sporophyte generation, species habitat selection, migration, and evolution. The sexual generation of club mosses-the gametophytes (or prothallia)-are among the least researched botanical subjects. Homosporous club mosses have an archaic life cycle, alternating two locationally, nutritionally, and physiologically independent generations. ![]()
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