Graptopetalum trujilloi A. Vázquez & Rosales, 2022

Vázquez-García, J. Antonio, Rosales-Martínez, C. Santiago & Acevedo-Rosas, Raúl, 2022, Graptopetalum trujilloi (Crassulaceae), a new haplostemonous and critically endangered species endemic to western Mexico: comments on taxa of subg. Glassia, Phytotaxa 532 (3), pp. 275-287 : 282

Graptopetalum trujilloi A. Vázquez & Rosales sp. nov. ( Figs. 3–5 ).

Diagnosis:— Graptopetalum trujilloi is similar to G. rosanevadoense in sharing a ramose habit, smooth stem surface and stem diameter, but it differs from the latter in having a smaller habit 15.0–35.0 (–41.0) vs. 40.0–87.0 cm, more numerous primary branches per inflorescence 8–10 vs. 5–7, larger mean flower density per 10.0 cm of the scape 16–20 vs. 6–14, fewer flowers per basal branch 3–6 vs. 7–8, smaller flower diameter 12.9–13.1 vs. 14.9–15.1, petals greenish with transversal inconspicuous red stripes vs. yellowish with transversal conspicuous red stripes, petal width 2.7–2.8 vs. 2.9–3.0 mm, filaments greenish to distally red vs. red and carpels abaxially obtuse vs. rounded. It is also similar to G. superbum in sharing a ramose habit, similar rosette diameter and similar mean flower density per 10 cm of the scape, but it differs from the latter in having a smaller habit 15.0–35.0 (–41.0) cm vs. 40.0–80.0 cm, stem surface smooth vs. squamose, smaller stem diameter 6.0–8.0 mm vs. 10.0–12.0 mm, less numerous primary branches per inflorescence 8–10 vs. 12–15, and smaller flower diameter 12.9–13.1 vs. 15.0–16.0 mm.

Type:— MEXICO, Jalisco: Municipio de San Gabriel, 4 km north of San Gabriel , Bosque de galería con Pittocaulon , Ficus , Salix . Abundante sobre laderas rocosas, 1350-1400 m, 19 April 2011, P. Carrillo-Reyes & J.M. Carrillo-García 6335 (holotype: IBUG!, Isotypes: CIMI!, ZEA!) .

Plants perennial, ramose, 15.0–35.0 (–41.0) cm tall without scape, branching basally; stems decumbent to pendant, surface smooth, brownish, 6.0–8.0 mm in diam. at the base, with oval to circular, bumped and dark greenish scars, 1.0–2.0 mm in diameter, the tip soon dried; each stem bearing a sparse terminal rosette 9.0–11.0 (–12.0) cm in diam.; leaves 15–32 per rosette, to 52 in cultivation, 4.0–7.5 × 2.3–2.8 cm, 6.0–9.0 mm thick, on an apical 4.0–7.0 cm stem, obovate, glabrous, base cuneate, adaxially slightly concave, abaxially convex, an apical mucro 1.0–3.0 × 1.0–3.0 mm, glaucous greenish to pinkish; scape 2.0–3.0 mm thick at the base, 1.0 mm thick on the upper part, gray-bluish to pinkish, mean flower density per 10 cm of the scape 16–20; panicle 15.0–32.0 cm long, dense, with 8–10 simple or bifurcate primary branches, with 30–50 flowers per inflorescence; bracts 1.0–3.0 mm long, lanceolate to elliptic; panicle primary branches 2.0–6.0 cm, simple or bifurcate, with 3–7 flowers each, 3–6 in the basal branch; pedicels 9.0–11.0 mm long; flowers 12.9–13.1 mm in diameter; petals (4–) 5, 2.7–2.8 mm wide, triangular, subequal, greenish with inconspicuous transversal red stripes, longitudinally with a shallow groove; stamens (4–) 5, erect in early stage of anthesis, later reflexed, filaments greenish to distally red; gynoecium yellow greenish to pinkish orange, carpels abaxially obtuse; fruits costate oblongoid, 5.0–6.0 × 2.0–3.0 mm; seeds unknown.

Distribution, habitat and phenology:— Graptopetalum trujilloi is known only from populations at the type locality, on the canyon of the Rio Tapalpa at an elevation of 1350-1410 m. The vegetation corresponds to the tropical deciduous forest with Bursera sp. , Heliocarpus sp. , Isolatocereus dumortierii , Lysiloma sp. , Pithecellobium dulce , Plumeria rubra , Pseudobombax sp. , Verbesina oligantha , V. tecolotlana , and Vitex sp. , among others. Plants form rock-dwelling dense colonies in North exposure vertical slopes along with Agave attenuata subsp. dentata , Astrolepis sinuata , Dioscorea sp. , Epidendrum examinis , Euphorbia sp. , Peperomia sp. , Pitcairnia sp. , Pittocaulon velatum Sedum chazaroi and Tillandsia aff. capitata ( Fig. 5 ). Flowering in early March. Fruiting in early June.

Eponymy and ethnobotany:—The specific epithet honours Jesús Trujillo Lara, an outstanding explorer of the Gran Barranca de Guadalajara and expert in succulent cultivation who contributed to the discovery of this species.

Additional specimens examined:— MÉXICO, Jalisco: 4 km north of San Gabriel , 1390 m, 7 September 2008, J. A . Vázquez-García 8835, with J . Trujillo , J . Etter , M . Kristen and M . Cházaro ( IBUG). Same location as previous, 4 km north of San Gabriel , 1410 m, 27 June 2021 (sterile), S . Rosales w/ C. Rosales and E. Martínez 1 ( IBUG), same location as previous, 27 June 2021 (infructescence), S . Rosales w/ C. Rosales and E. Martínez 2 ( IBUG) .

Figures

FIGURE 3. Graptopetalum trujilloi. A. Flower with reflexed stamens. B. Leaf. C. Plant showing pendant habit and full panicle with flowers and buds. Illustration by Santiago Rosales.

FIGURE 4. Graptopetalum trujilloi. A–B. Rosette adaxial and abaxial sides. C. Pendant crowded rosettes. D–E and G. Flowers with reflexed stamens (side and upright views). F. Dissected flower showing nectaries, and shape of carpels. H. Full panicle. I. Pendant ramose habit with distally curved stems. Photographs: A–B and I by Santiago Rosales, C–H by J. Etter & M. Kristen.

FIGURE 5. Habit and habitat of Graptopetalum trujilloi. A–B, D. Pendant rock-dwelling rosettes. C. Tropical dry forest in the Tapalpa micro watershed, San Gabriel, Jalisco. E. Santiago and Carlos Rosales reaching pendant rosettes. Photographs: A by Julia Etter & M. Kristen, B–D by Santiago Rosales and E by Endy Martínez.