PRUNINA   Kimnach & Moran, 1981 (engl./ fr.)

Series Gibbiflorae

Type : MacDougall B-138, on rocks at Mirador Cuesa, El Sumidero, near Tuxtla Gutierrez, ca 4000’ alt., Chiapas, Mexico.

Etymology :  pruninus lat., like a plum or prune : for the glaucous plum-coloured leaves.

Distribution: Mexico : Chiapas (at the type locality El Sumidero – apparently never found elsewhere).

Description by Reid Moran in Cactus and Succulent Journal US 53(6) : 295-298. 1981 :

Plant glabrous.

Stem to ca 10 cm long or more, 1 – 1.5 cm thick, often with aerial roots.

Rosette usually single, rather diffuse, with ca 15 – 25 leaves, 14 – 15 cm wide, to ca 5 cm high.

Leaves spathulate-obovate, somewhat asymmetrical, with one shoulder often more rounded than the other, obtuse, mucronate, 6 – 9 cm long, 6 – 10 mm wide at base, 2.5 – 4.5 cm wide ca 1.5 cm from apex, ca 5 mm thick at base, 2 – 3 mm thick near apex, strongly concave on upper surface when young, only slightly so when mature, obtusely keeled on lower surface, the margins rather sharp, the youngest leaves violet, heavily glaucous, the intermediate plum-coloured and lightly glaucous, the oldest bronzey reddish-green and non-glaucous, mucro subulate, terete, less than 1 mm long, reddened on young leaves, becoming obscure or lacking on older leaves.

Floral stems maturing from February to March, up to 3, erect to decumbent, (10-) 19 – 24 cm long, ca 5 mm thick at base and ca 3 mm thick just below cincinni, violet, glaucous ; leaves 10 – 15 (-25), more or less evenly spaced, ca 2 cm apart, the lower expanding, spathulate, not mucronate, the upper ascending, elliptic-oblong, with a mucro less than 1 mm long, all leaves below inflorescence obtuse, truncate or retuse, 18 – 43 mm long, 6 – 18 mm wide, 2.5 – 5 mm thick, the inner surface flat to convex, coloured like the stem leaves.

Inflorescence cymose-racemose, the cincinni 1 – 2, at first laxly circinnate, 6 – 11 cm long, with 6 – 14 flowers, the leaves elliptic to linear, acute, with a basal spur less than 2 mm long, 3 – 16 mm long, 1 - 6 mm wide, 1 – 3 mm thick, pedicels 4 – 8 mm long, 1 – 1.25 mm thick at base, gradually widening to 2 mm just below calyx, the bracteoles 1 – 2 mm long, 1 mm wide or less, deltoid.

Flowers : Calyx disc sub-umbilicate, 3 – 4 mm wide, some sinuses extending almost to the pedicel, the sepals ascending-spreading, markedly unequal, coloured like the leaves, the smaller ones lanceolate to sublinear, acute, 6 – 7 mm long, 2 – 2.5 mm wide, the larger ones elliptic-oblong, acute to obtuse, 8 – 16 mm long and 3 – 6 mm wide, corolla pentagonal in cross section, with flattened sides, 10 – 13 mm long, ca 8 mm thick 2 mm from base, ca 5 mm thick just below apex, ca 6 mm wide at apex, petals lanceolate, acute, connate 1.5 – 2.5 mm, the exterior glaucous-pink, reddish-orange beneath wax, the interior face coloured the same on apical third but light yellow below, ca 4 mm wide near base, ca 2 mm thick but channeled ventrally and hollowed basally to ca 1 mm deep, with a prominent nectar pit ca 2 mm wide and 3 mm long, subobtusely keeled dorsally, the margins acute, filaments 6 – 7 mm long, yellow.

Cytology : n = 28 +1

Distributed by ISI n° 1389 (1983)

Link to a summary of the above description in English and French.