Hoffmannseggia aphylla (Phil.) G.P.Lewis & Sotuyo

Lewis, G.P. & Sotuyo, J.S. 2010. Hoffmannseggia aphylla (Leguminosae: Caesalpinieae), a new name for a Chilean endemic. Kew Bulletin: 65 221. DOI: https://doi.org/10.1007/s12225-010-9201-8

Type

Chile: “Valle Tamarugal, Tarapacá; Quebrada de Tibivilche” (syntypes [fide Ulibarri 1996]: Tibivilche, in colis, “retamo” (fl.), fragment & photo SGO 49968 SI; Tarapacá, Tambillo Chico, “retama”, Hb. F. Philippi 1847, iii-1855 (fl., fr.), probable isosyntype SI; Tarapacá, photo F 1771 (fl) B: SI).

Morphology General Habit

Erect unarmed shrub, 2 – 3 m tall with bright green stems and leaves, or whole plant leafless; stems terete (although somewhat vertically ribbed on dry herbarium material), the young stems very short-appressed pubescent with retrorse white hairs, these can be so dense that the whole stem appears white, although plump orange coloured sessile glands are intermixed with the indumentum

Morphology Leaves

Leaves, when present, on very short brachyblasts or arising directly from new stem growth, each leaf with a single pair of pinnae; leaflets in 2 – 3 pairs per pinna, ovate-elliptic to round, thick and fleshy, sparsely pubescent, glabrescent, 1.5 – 2 × 1 mm, some leaflets with a slightly crenate margin and sessile glands in the depressions, leaflet venation not evident

Morphology Reproductive morphology Inflorescences

Racemes axillary or terminal, 1.5 – 2.5 cm long including a peduncle up to 5 mm long, 5 – 15-flowered, the rachis with patent white hairs, pedicels not articulated, patent pilose, 3 – 5 mm long, bracts lanceolate-triangular to ovate-orbicular, 0.5 – 1 mm long, the outer face pubescent, the jagged-fimbriate margin ciliate and sparsely glandular, caducous, buds and unfertilised flowers falling with pedicel attached to leave a horseshoe-shaped ledge on the inflorescence rachis, corolla golden yellow with bright red blotches on the standard petal blade forming a ring of contrasting colour around the circular opening to the claw apex, these nectar guides thus presenting a clear target for visiting pollinators, calyx tube 1.5 × 2.5 mm, patent pubescent, calyx lobes imbricate, pubescent with the hairs longer on the ciliate margins, the lobe apices rounded, emarginate or jagged-fimbriate, sometimes the fimbriae gland-tipped, standard petal with a narrow, inrolled glandular claw, 9.5 – 10 × 4 mm (including a claw of 3.5 mm), lateral petals 10 – 10.5 × 5 mm with less pronounced claws, stamen filaments with short-stalked glands on the lower \( \frac{2}{3} \), style lower \( \frac{1}{2} \) pubescent, widening towards the narrowly clavate, crateriform stigma, the opening with a rim of pollen-combing papillae

Morphology Reproductive morphology Fruits

Fruit a reddish brown, compressed-ovoid, coriaceous, dehiscent pod, c. 10 – 14 × 4 – 5 mm, with an acute apex, patent pubescent especially along the thickened margins, the valve surfaces with plump yellowish sessile to short-stalked glands, 1 – 3-seeded, the calyx and corolla becoming papery in texture and persisting to partially hide the mature fruit

Distribution

Chile.

Ecology

The species grows at the edge of salt lakes in low areas that receive runoff from surrounding uplands; amongst dunes with Prosopis chilensis, Atriplex sp. and Heliotropium sp.; along seasonally wet roadside plains surrounded by hyper-arid desert devoid of any vegetation; in sandy, clay soils; 780 – 2600 m.

Conservation

Although rare in herbaria outside Chile the species is apparently locally abundant and not threatened (Riedemannet al. 2006). Therefore it is given a conservation rating of Least Concern (LC).

Vernacular

Retama, retamo (Ulibarri 1996; Riedemannet al. 2006).