Leaves and stem of mimulus tilingii
may be hairless or lightly hairy. Leaves are broadly oval in shape, borne in a few opposite pairs at the base and along the short stems. They have a few small, well-separated teeth along the edges, and pronounced palmate veins, radiating from the attachment point. Leaves grow on short stalks.
The stem is topped by a small number (one to five) of yellow flowers, growing from the leaf nodes, on long pedicels - up to three inches. The green, ridged calyx is about one inch long, divided at the top into five small, somewhat unequal lobes. The tubular yellow flowers are quite large, up to 1.8 inches long. The lower surface of the inside of the corolla is flecked by red dots, rather smaller and fewer in number than some other species.
The common monkeyflower, mimulus guttatus
, is similar, the main differences being the greater number of flowers per stem (over five), and the flower positioning; in a branched raceme rather than at the leaf nodes.