Aechmea (E.Morren ex Mez) Harms.

Aechmea is a genus of flowering plants in the family Bromeliaceae - subfamily Bromelioideae.
The name comes from the Greek aichme, meaning "spear".
Aechmea comprises eight subgenera with 244 species and 73 infraspecific taxa (Nov. 2023) distributed from Mexico through South America and the Caribbean.
Most of the species in the genus Aechmea are epiphytes.

Aechmea includes some very discordant elements and is very likely of polyphyletic origin. Further research is likely to divide it with some parts becoming independent genera and others merging with genera at present considered distinct.

The eight subgenera are:
(Ref: Gouda, Eric J.; Butcher, Derek; Gouda, Kees (2022). "Aechmea". Encyclopaedia of Bromeliads.)
(Utrecht University Botanic Gardens. Retrieved 20 October 2022.)

Aechmea subgen 1. Podaechmea Mez, DC. Monogr.Phan.9:191. 1896.
Inflorescence amply compound, lepidote, lax.
Flowers pedicellate, polystichous.
Sepals mostly mucronate.
Petal appendages well developed.
Lectotype: Pironneava luddemanniana K. Koch, 1866.
(2023 now = Aechmea lueddemanniana (K. Koch) Mez)

Aechmea subgen 2. Lamprococcus (Beer) Baker, Handb.Bromel:33. 1889.
Inflorescence compound or simple, lax, glabrous.
Floral bracts mostly small to absent.
Flowers polystichous, sessile or pedicellate.
Sepals unarmed.
Petals appendaged.
Pollen porate.
Lectotype: Aechmea fulgens Brongniart, Ann. Sci. Nat. Bot. II. 15: 371. 1841.

Aechmea subgen 3. Aechmea Baker, 1889.
Inflorescence simple or compound, lax or dense but not strobilate.
Floral bracts and rhachis not forming pouches around flowers.
Flowers distichous or polystichous, sessile.
Sepals free or nearly so, unarmed (when flowers are distichous and lepidote) or mucronate;
petal appendages well developed.
Type: Aechmea paniculata Ruiz & Pavon, Fl. Peruv. 3: 37. 1802.

Aechmea subgen 4. Ortgiesia (Regel) Mez, 1892.
Inflorescence compound or simple, lax or dense, typically nidular but usually scapose.
Floral bracts not decurrent and not forming pouches.
Flowers sessile.
Sepals connate for one third to one half their length, their mucros about as long as their free lobes.
Petals distinctly appendaged.
Type: Ortgiesia tillandsioides Regel, Gartenflora 16: 193, pl. 547. 1867.
(2023 now = Aechmea recurvata (Klotzsch) L. B. Smith)

Aechmea subgen 5. Platyaechmea (Baker) Baker, 1889.
Inflorescence compound or simple, spikes dense.
Floral bracts decurrent and forming pouches.
Flowers distichous or polystichous, sessile.
Sepals free to one third connate, mucronulate or unarmed.
Petals distinctly appendaged.
Type: Aechmea distichantha Lemaire, Jard. Fleur. 3: pl. 269. 1853.

Aechmea subgen 6. Pothuava (Baker) Baker, 1889.
Inflorescence simple, never perennial, usually dense.
Floral bracts mostly not imbricate.
Flowers polystichous, sessile.
Sepals free or subfree, mucronate or mucronulate.
Petal appendages well developed.
Lectotype: Bromelia nudicaulis Linnaeus, Sp. Pl. 286. 1753.
(2023 now = Aechmea nudicaulis var. nudicaulis)

Aechmea subgen 7. Macrochordion (De Vriese) Baker, 1889.
Inflorescence simple, strobilate.
Floral bracts entire, unarmed.
Flowers polystichous, sessile.
Sepals unarmed; more or less connate.
Petal appendages well developed.
Type: Bromelia tinctoria Martius in Spix & Martius, Reise in Brasilien 2: 554.
1828: Linnaea 5: 42. 1830.
(2023 now = Aechmea bromeliifolia)

Aechmea subgen 8. Chevaliera (Gaudichaud ex Beer) Baker, 1889.
Inflorescence simple and strobilate or rarely digitate from a few spikes, often perennial.
Floral bracts coriaceous or ligneous.
Flowers in many ranks.
Sepals free or connate.
Petals with appendages reduced or lacking.
Type. Chevalieria sphaerocephala Gaudichaud, 1843.
(2023 now = Aechmea sphaerocephala)

Aechmea manzanaresiana, in the traditional classification of Smith and Downs (1979), could be placed in subgenus Platyaechmea. Members of this subgenus have sessile flowers mostly distichously arranged with conspicuous, imbricate floral bracts that conceal at least the ovary and usually most of the flower at anthesis and a spike rachis that is flattened and often broad and excavated.

The majority of the species have an Amazonian distribution.

Lectotype: A specimen chosen by a later researcher to serve as if it were the holotype. It is chosen from among the specimens available to the original publishing author (the isotypes, syntypes and/or paratypes) of a scientific name when the holotype was either lost or destroyed, or when no holotype was designated.
Type / type form: The originally collected plant from which a botanical description is written.
Holotype: The one specimen or illustration used by the author or designated by the author as the nomenclatural type.
Nomenclature: Naming of groups of organisms in conformity with an international code designed for precision and universal comprehension.
Subgenus: One of the divisions into which large genera are sometimes taxonomically divided.

Information compiled by Ross Little from: Aechmea genus and key to subgenera, The Butcher Files.
Bromeliad Society International - A Bromeliad Glossary and the internet.

Updated 20/11/23