Female plants protect and adjust their offspring through the morphology of synaptospermy after withering. This adjustment provides elasticity and guarantees heredity and reproduction for a given species. Synaptospermy is a critical characteristic of desert plants that evolved as an adaptation to harsh environmental conditions, and may have important ecological significance for the protection of seed function and cross-pollination between plants. Knowledge about this characteristic of the plant life cycle would increase our understanding about the adaptation strategies of synaptospermic plants in desert environments. Synaptospermy involves the joining of two or more seeds or one-seeded fruit to form a compound dispersal unit. This adaptation is common throughout the plant kingdom, but is largely restricted to arid regions. Out of the many morphological-ecological types that have been distinguished among synaptospermic plants, only a few are mentioned here. Synaptospermy is primarily derived from monospermy. Thus, this adaptation represents an advanced evolutionary stage associated with (1) the degeneration of separation tissues in pods, legumes, loments, and capsules, (2) the formation of abscission tissue in the joints of peduncles and pedicels, and (3) a series of other characteristics. In fact, synaptospermic species are found in genera belonging to phylogenetically advanced groups within their respective families, such as the Brassicinae, Galegeae, Hordeae, and Paronychieae. Fruit that contains synaptospermic seeds are able to establish physiological gradients;thus, spreading germination over time (a major advantage). The dispersal and spreading of germination over time (polyphenic germination) allows a mother plant to reduce competition among its offspring. Polyphenic germination is especially pronounced in synaptospermic seeds. Synaptospermy may be divided into two morphologically different types: (1) diaspores develop from the joined seeds of the carpels of one flower, and (2) diaspores develop from the units of different flowers. None of these dispersal units, which contain up to several seeds in a single diaspore, develops more than two seedlings in one season, indicating that all seeds remain together in the dispersal unit, but are ready to germinate in different years;this phenomenon is called intermittent germination. The annual Tribulus terrestris and the perennial Marrubium vulgare are synaptospermic plants with dispersal units belonging to the two morphologically different diaspore types;M. vulgare also disperses using seeds. Here, we conducted preliminary comparisons and observations on the morphology, vigor, water absorption, and germination characteristics of each dispersal unit. The results showed that mass, length of burs, percentage of appendages accounting for mass, number of seeds, vigor, and water absorption all significantly differed among the synaptospermies of T. terrestris. Conversely, while mass and water absorption significantly differed among M. vulgare dispersal units, no significant differences were observed for vigor, germination, and germination rate. The position of germination in synaptospermy differed between plants. For instance, seeds only germinated on the long thorns of synaptospermids in T. terrestris, indicating nonrandom germination, but no regularity in germination was observed for M. vulgare, indicating random germination. In addition, under the conditions with the highest germination percentage, only part of the seeds germinated in one season for both species, indicating intermittent germination. For different plant life forms, the synaptospermic appendage has the same functions, e.g., protecting seeds, retaining water, dispersing, and germinating. However, the germination behavior of annual plants focuses on population reproduction;therefore, the germination percentage of synaptospermy was high over the season for T. terrestris. Conversely, the germination behavior of perennial plants focuses on population dispersal;therefore, the dispersal units of M. vulgare showed diverse characteristics, with a low germination percentage for the dispersal units over the season.