Ceratozamia osbornei D.W.Stev., Mart.- Dominguez & Nic.-Mor., 2022

Martinez-Dominguez, Lili, Nicolalde-Morejon, Fernando, Vergara-Silva, Francisco & Stevenson, Dennis Wm., 2022, Monograph of Ceratozamia (Zamiaceae, Cycadales): an endangered genus, PhytoKeys 208, pp. 1-102 : 1

25. Ceratozamia osbornei D.W.Stev., Mart.- Dominguez & Nic.-Mor. sp. nov.

Figs 5 , 6

Diagnosis.

Similar to Ceratozamia robusta and C. subroseophylla , but distinguished by characters of reproductive structures. It has megasporophylls with abundant purple to wine-colored trichomes, ovulate strobili with an acuminate apex and up to 12 orthostichies with 31 sporophylls per orthostichy and pollen strobili with a long infertile portion from 0.65 to 0.80 cm long.

Type.

BELIZE. Toledo: Southwestern Maya Mountains, Columbia River Forest Reserve , Union Camp. 6 Apr 1992, B.K. Holst 4105 (holotype: NY! [01340569]; isotype: MO! [acc. # 04661737, 04661738]) .

Description.

Stem 30-200 cm long, 20-40 cm in diameter, epigeous, generally decumbent. Cataphylls 5.5-8 × 2-3 cm wide at the base, persistent, triangular, reddish brown, brown tomentose at emergence, glabrous at maturity, apex acuminate. Leaves 12-50, 90-300 cm long, ascending, brown at emergence, with whitish gray trichomes, glabrous at maturity. Petiole 75-100 cm long, terete, linear, greenish brown or dark brown at emergence, green in mature leaves; with 20-40 robust prickles, 0.20-0.45 cm long. Rachis 90-200 cm long, terete, linear, greenish brown or dark brown at emergence, green in mature leaves, with prickles. Leaflets 26-51 pairs, opposite to subopposite, insertion in one plane, lanceolate, longitudinally curved abaxially to planar, not basally falcate, papyraceous, flat, dark green, adaxial side glabrous, abaxial side glabrous, distal end with entire margins, acuminate and symmetric at the apex, attenuate at base, with conspicuous and light-green veins; median leaflets 30-45 × 2.5-4.0 cm, 1.7-5 cm between leaflets; articulations 0.9-1.6 cm wide, brown in young leaves and green in mature leaves. Pollen strobili 60-80 cm long, 7-9 cm in diameter, solitary, cylindrical, erect, green with wine trichomes at emergence, greenish yellow at maturity with wine to purple trichomes; peduncle 7-11 cm long, 2.5-3.5 cm in diameter, tomentose, brown; microsporophylls 2.0-3.3 × 1.1-1.85 cm, obconic with a non-recurved distal face and deeply lobate fertile portion, infertile portion 0.65-0.80 cm long and rounded with straight horns 0.20-0.29 cm long, 0.55-0.75 cm and a right angle between the horns. Ovulate strobili 30-50 cm long, 9-14 cm in diameter, solitary, cylindrical, erect, green with abundant wine to dark purple trichomes at emergence, green with abundant dark purple trichomes at maturity, acuminate apex; peduncle 12-20 cm long, 2.5-4.5 cm in diameter, erect, tomentose, reddish brown; megasporophylls 108-280, 9-12 orthostichies with 12-31 sporophylls per orthostichy, 1.8-2.3 × 2.3-4.1 cm, with a prominent distal face, horns straight and 0.36-0.50 cm long, 0.90-1.35 cm between horns with a right angle between the horns. Seeds 3.0-4.5 cm long, 2.0-3.0 cm in diameter, ovate, sarcotesta whitish pink when immature, light brown at maturity.

Distribution and habitat.

Ceratozamia osbornei is endemic to Belize (Fig. 22A ), where it occurs in evergreen tropical forest on karstic rocks with abundant organic matter between 200 and 750 m elevation.

Etymology.

The specific epithet honors Roy Osborne in recognition of his remarkable contributions to the knowledge of the cycad diversity in the world. In particular, he has actively participated in the project "The World List of Cycads" since its inception (https://www.cycadlist.org).

Common names.

None recorded.

Uses.

None recorded.

Conservation status.

There is insufficient data for evaluation, but it is known that some populations have more than 100 plants.

Paratypes.

BELIZE. Cayo: 19 Aug 2008, M. Calonje et al. BZ08-042 (FTG); 20 Aug 2008, M. Calonje et al. BZ08-056 (FTG); 25 Feb 1992, C. Hubbuch et al. (FTG); 6 Apr 1971, S. Kiem s.n. [027932] (FTG); Spring, 1973, S. Kiem s.n. [027929] (FTG); 550 m, 4 Aug 1980, Sutton et al. 15 (MEXU, MO); 455 m, 12 Dec 1996, T. Hawkins 1186 (NY, MO). Toledo: 750 m, 15 May 1979, C. Whitefoord 1764 (BM); 800-1,200 m, 23-27 Apr 1976, G.R. Proctor 35985 (BM, MO).

Figures

Figure 5. Illustration of Ceratozamia osbornei A pollen strobilus at maturity B variation of leaflets C microsporophyll D ovulate strobilus at maturity E adult plant A-C based on B. K. Holst 4105 and D, E based on cultivated plant in Fairchild Tropical Botanic Garden.

Figure 6. Ovulate strobilus of Ceratozamia osbornei A immature ovulate strobilus B mature ovulate strobilus. These photos were taken in Fairchild Tropical Botanic Garden.

Figure 22. Distribution of Ceratozamia species. A C. osbornei B C. robusta C C. sabatoi D C. sancheziae.