Dudleya marcescens (Moran) P. H. Thomson

Caudices often branching, 0.2-0.7 cm diam. Leaves withering in summer; rosettes 8-15-leaved; blade green, oblanceolate, 1.5-3(-5) × 0.5-1.5 cm, apex acute to subobtuse, surfaces not farinose, glaucous. Inflorescences: floral shoots 5-15-leaved, 4-10 cm; cincinni 1-2, (1-)3-5-flowered, 1-4 cm. Petals bright yellow, often marked with red, 10-14 × 2.5-3.5 mm. 2n = 34.

Flowering spring. With moss and lichens in very thin soil on sheer north-facing cliffs; of conservation concern; 300-400 m; Calif.

Subspecies marcescens is known from the Santa Monica Mountains, Ventura and Los Angeles counties; it is considered fairly threatened (California Native Plant Society, http://cnps.web.aplus.net/cgi-bin/inv/inventory.cgi). This is the most distinct and distinctive of the subspecies of Dudleya cymosa, very different from subsp. cymosa but more or less connected by subsp. ovatifolia, also in the Santa Monica Mountains. It differs in its slender caudex, small leaves, and few flowers, and is one of only two members of subg. Dudleya whose leaves wither in early summer and are not replaced until after the first rains, often in late fall. The other is D. parva, growing some 13 kilometers to the north. In habit, they resemble subg. Hasseanthus, which differs in its slow-growing underground stems with crowded leaves and its open flowers. As noted by M. Dodero (1996), these two also are paedomorphic forms.