Sedum

HUTCHISONII  Kimnach & Low ex Pino & Cieza, 2020

Type : Hutchison, Wright & Straw 6621, 7 km above Huancabamba, Dept. Piura, Peru, 2456 m, sep 17, 1964.

Distribution : Peru (Dept. Piura, Cajamarca & La Libertad). 

Description :

 A succulent glabrous herb, subcaespitose, forming mats to 10–15 cm diam., 6–15 cm tall. 

Roots fibrous, scarce, 2–5 cm long, 0.2–0.3 mm diam., growing inside moss.

Stem in young plants 1.3–2 mm diam., 3–5 cm long, erect, then branching alternately from base and sides, light greenish gray, in old plants procumbent at base, with scars, 4–5 mm diam., 5–7 cm long, light gray-brownish.

Branches born every 1–3 cm, 10–15, erect to slightly decumbent, 4–10 cm long, stem 1.8–2.8 mm diam., light greenish gray. Stems of vegetative branches 6–8 mm diam., altogether covered with leaves, stems of reproductive branches 8–10 mm diam., altogether covered with leaves.

Leaves succulent, sessile, spirally attached to stem, in vegetative branches crowded; in reproductive branches slightly more distanced towards apex, up to 1–2 mm apart,  ovate and subfaceted when young or near apex, later narrowly ovate, obovate or terete-conical, base inserted in a right angle with stem, 4–7 mm long, 2–3.5 mm wide, 2–3 mm thick, apex obtuse or rounded, both sides convex, rarely abaxial side subcarinate, sometimes adaxial side slightly incurved at distal third in leaves near flowering apex, bright to olive green with reddish dots where exposed, margins blunt, base hyaline light green.

Inflorescence a terminal cyme (dichasium) with 2 cincinnoid branches (rarely a monochasium) 1–1.2 mm diam. at base, gradually tapering, 0.2–2 cm long, light green.

Flowers 1–7 per cincinnus, sessile, rarely with up to a 1 mm diam., pedicel 2 mm long, flower buds ovoid, 2–2.2 mm long, 1.6–1.8 mm diam., dark burgundy red. Bracteoles : one at the base of each flower, oblong to narrowly ovate, 2.2–3.6 mm long, 1.5–1.8 mm wide, subacute, upper side flat,  lower side convex, light green. Sepals oblong to narrowly ovate, 2–3 mm long, 0.6–1 mm wide,  erect, outer side burgundy red except at base, inner side light green. Petals oblong to narrowly ovate, acute-deltoid at tip, erect proximally, then bending outward above the middle in 90º or totally reflexed, 1.8–2 mm long at the erect portion, 1–1.3 mm long at the reflexed portion, 1–1.3 mm wide, greenish yellow, dark brownish at keel and distal third of outer side, inner side greenish yellow with a slight blush at distal half near margins. Flower diam. 2.2–2.5 mm at base, 3.5–5 mm diam. at expanded petals. Stamens 10, the 5 epipetalous 1.8–2.2 mm long, the antesepalous 2.3–2.5 mm long, filaments greenish yellow 0.1–0.2 mm diam. Anthers globose, yellow, 0.2 mm diam. Gynoecium narrowly ovoid, 1.5–1.6 mm long,  1.2–1.4 mm diam. Carpels 5, greenish yellow. Style 0.5–0.6 mm long, greenish yellow, stigma inconspicuous. Nectaries lunate, greenish yellow, 0.3–0.4 x 0.2 mm. Fruit  appearing in habitat from February  to March, 4–5 mm long, 3–4 mm diam., unripe light green, then dehiscent light brown, star–shaped from above.

Flowering time in habitat from January to February.

First published in CSJ US 92(4), 292-298, 2020.

 

 

In habitat near Huancabamba :

Photo Guillermo Pino

In habitat at Jesús, Cajamarca :

Photo Nelson Cieza

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