This species is characterized by its stems with a distinctive form, its stipules shortly united around the stem and on each interpetiolar side truncate to broadly rounded with a medial group or line of glands, its elliptic leathery leaves, its pedunculate few-to several-flowered inflorescences, its calyx limbs that are divided to the base into acute triangular lobes, and its funnelform corollas with the tubes 20-23 mm long and the lobes appendaged at the tip in bud. The stems are characteristically gradually enlarged from the base to the top of a node, so that the portion of the stem below the node is markedly wider in diameter than the basal portion of the internode above it. The leaves of the dried specimen are discolorous with the lower surface yellowed as well as paler. The stipule form can be difficult to discern, because the stipules apparently are imbricated in bud so that the glandular setae are at its top and the glabrous portion above them is bent over and not visible. Thus at the vegetative apices the stipules appear to be ligulate with the glands at its tip. However when the stipules unfold the setae are clearly inserted in a medial horizontal line, which quickly then becomes scar.

Rudgea garciana is so far apparently only known from a very few specimens, possibly only two. It is similar vegetatively to Rudgea ciliata and some fruiting specimens that are now identified as that species may actually belong to Rudgea garciana. However Rudgea ciliata differs from Rudgea garciana in its pilosulous multi-flowered inflorescences with smaller flowers, with the corolla tubes 4--6 long.