Pseudomonopodial in growth habit of monotypic stands. Displays characteristics of both Rhyniophytes and Zosterophyllophytes. A silicified Devonian peat bog known as the Rhynie Chert is one locality in which many of the earliest vascular plants were first identified. Cauline sporangia are clustered near the top of the axes. Commonly found as monotypic assemblages.
Lateral spines have no vascular tissue.
Commonly found in monotypic assemblages. Gosslingia - Aerial stems up to 0.5 m in height with dichotomous branching but a strong centralized axis resulting in an imperfect pseudomonopodial habit. Commonly found as monotypic assemblages Rebuchia - Plant of densely branched, tufted aspect with distinct upright axes up to 15 cm in height. Some dichotomous axes terminated by dense clusters of stalked, opposite to subopposite sporangia. Stem with variously shaped spines.