It is a Lamb's quarters.

Scientific name: Chenopodium album.

A fast-growing annual herb with an upright to somewhat branching habit, often reaching 30–150 cm tall when mature. Stems are green, sometimes reddish-tinged, and may be lightly grooved. Leaves are alternate and borne on slender petioles; they are variable in shape but commonly triangular to diamond-shaped or broadly ovate, with irregular shallow teeth or lobes along the margins. The leaf surface is dull green to gray-green, and young leaves and growing tips often have a pale, powdery or mealy coating. Mature plants produce small, inconspicuous green flowers clustered in dense spikes or branched panicles at the stem tips and leaf axils, followed by many tiny dark seeds..

Lamb's quarters is closely related to quinoa, and its young leaves are edible when properly prepared; in many places it has long been used as a wild spinach-like green..

The plant shows several key features typical of lamb's quarters: alternate petiolate leaves, triangular to diamond-shaped blades, irregularly toothed margins, and a muted gray-green coloration with a slightly mealy appearance on some young leaves. Its growth in a disturbed rocky crevice also fits this common weedy species. The image does not show flowers or seeds, which are important for confirming Chenopodium album versus closely related goosefoots or saltbushes, so the identification is moderately high rather than certain.