Dioon Lindley 1843
Creators: name: Gutiérrez-Ortega, José Said
name: Pérez-Farrera, Miguel Angel
name: Chemnick, Jeffrey
name: Gregory, Timothy J.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Cycadopsida
Cycadales
Zamiaceae
Dioon

description: Key to the Dioon species in the Purpusii clade
Dioon salas-moralesae, Dioon merolae and Dioon oaxacensis belong to the Purpusii clade, as determined in previous phylogenetic studies (Gutiérrez-Ortega et al., 2018b, 2018c; Dorsey et al. 2018). The other species in this clade are Dioon argenteum, Dioon califanoi De Luca & Sabato (1979: 170–172), Dioon caputoi De Luca, Sabato & Vázquez Torres (1980: 44–46), Dioon holmgrenii (1981b: 552–554), Dioon planifolium, and Dioon purpusii Rose (1909: 260– 261). A key for the species of the Purpusii clade is here provided.
1a. Leaves green when emerging .............................................................................................................................................................2
1b. Leaves silver when emerging ......................................................................................................................................... D. argenteum
2a. Leaflets strongly curved downward in the apical portion .................................................................................................. D. merolae
2b. Leaflets not or slightly curved downward in the apical portion.........................................................................................................3
3a. Leaflets strongly imbricated...............................................................................................................................................................4 3b. Leaflets not imbricated.......................................................................................................................................................................6
4a. Leaflets inserted obliquely on the rachis, leaf strongly keeled ......................................................................................... D. califanoi
4b. Leaflets not obliquely inserted on the rachis......................................................................................................................................5
5a. Leaflets flat, leaf frequently moderately keeled............................................................................................................ D. oaxacensis
5b. Leaflets slightly curved downward in the apical portion ...................................................................................... D. salas-moralesae
6a. Leaves moderately keeled ................................................................................................................................................. D. purpusii
6b. Leaves not keeled ...............................................................................................................................................................................7
7a. Leaflets 4–5 mm wide, widely spaced along the rachis ...................................................................................................... D. caputoi
7b. Leaflets> 5 mm wide, slightly spaced along the rachis......................................................................................................................8
8a. Leaflets with 3–4 long spines on the upper margin and slightly decurved ................................................................... D. holmgrenii
8b. Leaflets flat with 0–2 long spines on the upper margin ............................................................................................... D. planifolium
description: Published as part of Gutiérrez-Ortega, José Said, Pérez-Farrera, Miguel Angel, Chemnick, Jeffrey & Gregory, Timothy J., 2021, A reassessment of Dioon merolae (Zamiaceae) leads to the description of Dioon salas-moralesae, a new cycad species from Southeastern Oaxaca, Mexico, pp. 93-110 in Phytotaxa 528 (2) on pages 104-105, DOI: 10.11646/phytotaxa.528.2.3, http://zenodo.org/record/5778682