Primary thallus: squamulose, persistent; squamules: 7-12 mm long, 3-8 mm wide, entire to irregulary crenate-lobate to shallow subdigitately lobate; esorediate or with granular, soredia-like structures forming beneath margins; veins: appearing toward base on the lower side podetia: 3-10 (20) mm tall, whitish green to gray, cup-forming; cups: 1-8 mm wide, surface: lacking a cortex, or with immediate basal area corticate, granulose, soft-appearing, with pillow-like schizidia (80-200 micro meter diam) occurring immediately above base giving rise to small peltate squamules and isidioid structures, rarely enlarging to form podetial squamules, abundantly covered with granulose soredia and peltate squamules; margins: producing numerous (5-23) blunt, digitate proliferations, or proliferations expanding to form cups, rarely giving rise to further proliferations Apothecia: rare, borne singly along cup margins or at tips of proliferations, dark reddish brown ascospores: not seen conidia: rare, not seen Spot tests: K+ yellow, C-, KC-, P+ orange, changing to red, UV- Secondary metabolites: atranorin, bourgeanic acid, fumarprotocetraric acid, but according to Ahti (2000) atranorin sometimes absent (and bourgeanic acid may be difficult to identify due to low concentration). Habitat and ecology: on bare soil banks World distribution: Europe and North America; probably also West Indies and South America Sonoran distribution: Arizona and southern California, and Baja California (Guadalupe Island). Notes: Cladonia pulvinella possesses large (to 200 Ķm), loosely corticate structures that fill the cup interiors and which resemble soredia. Although C. hammeri has similar granules on its surface, it lacks bourgeanic acid. The presence of C. pulvinella in the study area is somewhat uncertain, although it was reported from Los Angeles Co., California by Hammer (1995) and Baja California by Ahti (2000); the records from Arizona and Baja California are based on Ahtiís identification based on morphology. Because of the recognition of C. hammeri in this treatment, all material needs to be re-examined and analyzed with chromatography to identify the simultaneous presence of bourgeanic acid and atranorin, which is diagnostic of C. pulvinella, even though (Ahti 2000) included material without atranorin. In any case, C. pulvinella is found further north in California (see Hammer 1991 & 1995) and is expected to occur in the Sonoran Region. See further the discussion under C. hammeri.