Renalia is a genus of extinct vascular plants from the Early Devonian (around 420 to 390 million years ago).

As with all compressions, it is difficult to reconstruct the entire plant, but the sporophyte is thought to have been about 30 cm tall, with bare stems (axes) up to 1.5 mm wide.

The rounded to reniform (kidney-shaped) sporangia (spore-forming organs) were born at the tips of the lateral branches and dehisced (split) along the distal margin into two equal parts.

[4] The absence of leaves, the presence of vascular tissue, the terminal position of the sporangia and the form of the branching of the stems (pseudomonopodial) suggest a relationship with the Rhyniaceae; however, the shape of the sporangia and the form of their dehiscence suggest a relationship with the lycophytes.

[3] Hence the position of the genus in the cladogram for the polysporangiophytes which Crane et al. published in 2004; Renalia is placed basal to the lycophytes (clubmosses and relatives).