Ceratozamia alba Pérez-Farr., Gut., 2024

Pérez-Farrera, Miguel Á., Martínez-Martínez, Mauricio G., Moreno-Méndez, Gaspar, Vovides, Andrew P. & Gutiérrez-Ortega, José Said, 2024, Ceratozamia alba (Zamiaceae): A new cycad species from the Selva El Ocote Biosphere Reserve in Chiapas, Mexico, Phytotaxa 666 (4), pp. 257-276 : 265-268

Ceratozamia alba Pérez-Farr., Gut. -Ortega & Vovides sp. nov. ( Figs. 5–11 ).

Type: — MEXICO. Chiapas, Northern Mountains, Selva El Ocote Biosphere Reserve, 9 July 2023, M. A Pérez-Farrera & M. Martínez-Martínez 4396 ♀ (Holotype: HEM!, isotypes: CHIP!, XAL!)

Diagnosis:— Ceratozamia alba is distinguished from all other Ceratozamia species by having circinate vernation, emerging leaves of whitish green to light green, changing to blue green pruinose and light green when mature, arched mature leaves, leaflet articulations on the adaxial side light green to yellowish, trunks erect and short and thin trunk when old, megastrobili erect, bluish-green, and microstrobili light green to yellowish-green with reddish tomentum.

Plant rupicolous. Stem unbranched, short or thin, elongated when old, cylindrical, erect, decumbent with age, covered with persistent leaf bases, 16–30 cm tall, 9–22 cm in diameter. Cataphylls persistent, brown and densely tomentose at emergence, triangular, apex acuminate. Leaves pinnate, 4–17 per crown, forming an open crown, erect, ascending when young, descending with age, 140–241.3 cm long, 52.5–76.4 cm wide, emerging whitish-green, glaucous, turning bluish-green, and finally olive green at maturity, vernation circinate, pruinose during maturation. Petiole terete, ochre, 51.8–104.6 cm long, armed with short and thin, scattered prickles. Rachis terete, green, 48–109.6 cm long, erect, with sparse prickles diminishing distally. Leaflets 14–27 pairs, linear, long lanceolate, coriaceous, basally subopposite to alternate, medially subopposite to opposite, apically opposite to subopposite, basally slightly sub-falcate or linear, medially and apically linear, margin entire, apex acute to acuminate, asymmetric; median leaflets 27.2–38.7 cm long, 2.2–3.5 cm wide, spaced 1.8–5.9 cm between leaflets; base broad attenuate, articulation dark green abaxially and light green to yellowish adaxially, 0.73–1.42 cm wide; veins 15–22, parallel, prominent; seedling eophylls 2. Microstrobilus solitary, conical, erect, light green to yellowish-green when mature, 15.90–16.5 cm long, 3.4–3.5 cm diameter, peduncle densely tomentose, light brown, 1.1–1.5 cm long, 1.1–1.2 cm diameter. Microsporophylls cuneiform, 10.55–11.52 mm long, 6.2–8.1 mm wide, distal face bicornate, reddish centrally, sporangia zone on abaxial surface 6.05–7.0 mm long, microsporangia grouped in 3–4 per sorus. Megastrobilus solitary, cylindrical, erect, 21.6–24 cm long, 8–9 cm diameter, bluish green; apex apiculate, blackish to reddish pubescent at mature, peduncle densely tomentose, short, light brown and reddish, 6–10 cm long, 1.8–2.3 cm in diameter. Megasporophylls peltate, bluish green, bicornate, 4.4–5.4 cm wide, 2.3–2.5 cm tall, distal face pubescent blackish to reddish toward the margins and horn bases when mature, horns yellowish brown. Seeds ovoid, sarcotesta cream when immature, sclerotesta beige when mature, with micropylar ridges, 14.5–28.8 mm long, 14.5–17 mm wide.

Distribution and habitat:— Ceratozamia alba is endemic to the Selva El Ocote Biosphere Reserve in the mountains of northern Chiapas, Mexico. Only one population of this species has been found, and it grows on karstic rocks in tropical rainforest between 700 and 800 m a.s.l. This species is accompanied by some floristic elements at different strata. Tree stratum: Platymiscium dimorphandrum Donn. Sm. (1904: 208) , Oreopanax sp. , Dendropanax sp. , Guarea sp. , Dracaena americana Donn. Sm. (1905: 207) , sp., Trichilia sp. , Neea psychotrioides (1891: 199), Eugenia sp. , Ficu s sp., Clusia sp. Shrub stratum: Gaussia sp. , Chamaedorea ernesti-augusti Wendland (in Otto & Dietrich 1852: 73), Chamaedorea glaucifolia H.Wendl (1854: 64) , Chamaedorea oblongata Martius (1838: 160) , Astrocaryum mexicanum Liebmann ex Martius (1853: 323) , Bouvardia sp. Shrub stratum: Calathea sp. , Anthurium huixtlense Matuda (1950: 91) , Anthurium faustomirandae Pérez-Farr. & Croat (2001: 88) , Anthurium schlechtendalii Kunth (1841: 75) , Begonia sp , Pitcairnia sp , Philodendron sp. Epiphytes: Monstera acuminata Koch (1855: 4) , Peperomia sp. , Polypodium sp.

Etymology:— Ceratozamia alba is named for its most distinguishable trait, the whitish-green color of its emerging leaves, unique in the genus.

Conservation status:—In Selva El Ocote, only three agglomerates of individuals of C. alba can be found within an area of approximately 0.1 km 2 (10 ha); we consider the three agglomerates to belong to a same population. The population is small (less than 50 adult individuals). Thus, the species must be considered Critically Endangered (CR) in the IUCN Red List of Threatened Species (IUCN 2023). Therefore, precise locality information is not given in order to avoid illegal collecting. The region is also being converted to pasture for livestock, corn, coffee cultivation and stone material for construction is being extracted as well. Its conservation in situ is urgent as well as ex situ conservation in botanic gardens through rescue and propagation programs (Vovides et. al. 2002).

Additional specimens examined: — MEXICO. Chiapas, Mexico, Selva El Ocote Biosphere Reserve, Northern Mountains , 7 March 2023, M. G Martínez-Martínez & J. Garcia Gonzalez 102 ( HEM) ; 1 April 2023, M. A. Pérez-Farrera & M. Martínez-Martínez 4354 ♂ ( HEM) ; 1 April 2023, M. G. Martínez-Martínez & M. A. Pérez-Farrera 116 ( HEM) ; 9 July 2023, M. G Martínez-Martínez et al. 124 ( HEM) ; 22 July 2023, M. Martínez-Martínez & Moreno Méndez G. 153 ( HEM) ; 12 November 2022, M. A Pérez-Farrera et al. 4332 ( HEM) ; 18 March 2019, M. A. Pérez-Farrera 3750 ( HEM) .

Figures

FIGURE 5. (A–B) Adult plants of Ceratozamia alba sp. nov. in habitat.

FIGURE 6. Ceratozamia alba sp. nov. (A) Emerging leaf showing the characteristic whitish color and circinate vernation, (B) Second phase of leaf maturation (abaxial leaflet surface is pruinose). (C) Third phase of leaf maturation. (D) Mature phase of leaf. (E) Mature leaf in adult plant. (F) Rupicolous habit of C. alba: plants grow from holes or fissures in the karst rocks.

FIGURE 7. Ceratozamia alba sp. nov. presents color variation of their leaves during maturation. Younger leaves are bluish green (blue arrow at the right side), and mature leaves are light green (yellow arrows at the left side).

FIGURE 8. Ceratozamia alba sp. nov. (A) Immature megastrobilus. (B) Maturing megastrobilus. (C) Mature megastrobilus. (D) Seedling with two eophylls. (E) Abaxial view of leaflets (note the veins). (F) Mature microstrobilus.

FIGURE 9. (A) Immature megastrobilus of Ceratozamia alba sp. nov. visited by Eumaeus debora (Lycaenidae). (B) During maturation, the megastrobilus of C. alba turns a bluish green color.

FIGURE 10. Holotype of Ceratozamia alba sp. nov. Geographic coordinates of the original locality are hidden to discourage illegal collecting.

FIGURE 11. Reproductive structures of the holotype of Ceratozamia alba sp. nov. Geographic coordinates of the original locality are hidden to discourage illegal collecting.