Accepted Genus
First published in: Sp. Pl.: 1188 (1753)
Etymology: From the Greek Koikas, a kind of palm
Synonyms:
Description: Habit: dioecious palm like shrubs with aerial or subterranean, pachycaul, cylindrical stems. Leaves: pinnate or rarely bipinnate, spirally arranged, produced in seasonal growth flushes interspersed with cataphylls, lower leaflets often reduced to spines. Longitudinal ptyxis erect or rarely reflexed, horizontal ptyxis circinate. Leaflets with a single thick midrib and no lateral veins; stomata confined to abaxial surface in most species; individual ptyxis involute. Leaves pubescent, at least when young, with branched or simple transparent hairs. Microsporophylls: aggregated into determinate male cones and each with a simple sterile apex, which is often produced into an upturned spine. Each microsporophyll bearing numerous microsporangia (pollen sacs) on its abaxial surfaces. Microsporangia opening by slits. Pollen cymbiform, monosulcate. Megasporophylls: loosely or tightly imbricate, spirally arranged in an indeterminate terminal rosette with the central axis continuing vegetative growth. Ovules two to many (rarely one), marginally inserted on the stipe and directed obliquely outwards (`ascending'). Megasporophyll apically dilated into a pinnatifid, pectinate, toothed or entire lamina in the distal zone beyond the ovule-bearing stipe. Seeds: subglobular to ellipsoidal, with a yellow, orange or brown fleshy outer sarcotesta, and with or without spongy tissue beneath the inner woody sclerotesta. Endosperm haploid, derived from the female gametophyte. Embryo straight; with 2 cotyledons that are usually united at the tips and a very long, spirally twisted suspensor. Seeds platyspermic; germination cryptocotylar.
Included Species
(119 species and 6 infraspecific taxa )
- Cycas aculeata
- Cycas aenigma
- Cycas angulata
- Cycas annaikalensis
- Cycas apoa
- Cycas arenicola
- Cycas armstrongii
- Cycas arnhemica
- Cycas badensis
- Cycas baiseensis
- Cycas balansae
- Cycas basaltica
- Cycas beddomei
- Cycas bifida
- Cycas bougainvilleana
- Cycas brachycantha
- Cycas brunnea
- Cycas cairnsiana
- Cycas calcicola
- Cycas campestris
- Cycas canalis
- Cycas candida
- Cycas cantafolia
- Cycas chamaoensis
- Cycas changjiangensis
- Cycas chenii
- Cycas chevalieri
- Cycas circinalis
- Cycas clivicola
- Cycas collina
- Cycas condaoensis
- Cycas conferta
- Cycas couttsiana
- Cycas cupida
- Cycas curranii
- Cycas debaoensis
- Cycas desolata
- Cycas dharmrajii
- Cycas diannanensis
- Cycas distans
- Cycas divyadarshanii
- Cycas dolichophylla
- Cycas edentata
- Cycas elephantipes
- Cycas elongata
- Cycas falcata
- Cycas ferruginea
- Cycas flabellata
- Cycas fugax
- Cycas furfuracea
- Cycas glauca
- Cycas guizhouensis
- Cycas hoabinhensis
- Cycas hongheensis
- Cycas indica
- Cycas inermis
- Cycas javana
- Cycas lacrimans
- Cycas lane-poolei
- Cycas laotica
- Cycas lindstromii
- Cycas maconochiei
- Cycas maconochiei subsp. lanata
- Cycas maconochiei subsp. maconochiei
- Cycas maconochiei subsp. viridis
- Cycas macrocarpa
- Cycas media
- Cycas media subsp. banksii
- Cycas media subsp. ensata
- Cycas media subsp. media
- Cycas megacarpa
- Cycas micholitzii
- Cycas micronesica
- Cycas mindanaensis
- Cycas montana
- Cycas multifrondis
- Cycas multipinnata
- Cycas nathorstii
- Cycas nayagarhensis
- Cycas nitida
- Cycas nongnoochiae
- Cycas ophiolitica
- Cycas orientis
- Cycas orixensis
- Cycas pachypoda
- Cycas panzhihuaensis
- Cycas papuana
- Cycas pectinata
- Cycas petraea
- Cycas platyphylla
- Cycas pranburiensis
- Cycas pruinosa
- Cycas pschannae
- Cycas revoluta
- Cycas riuminiana
- Cycas rumphii
- Cycas sancti-lasallei
- Cycas saxatilis
- Cycas schumanniana
- Cycas scratchleyana
- Cycas seemannii
- Cycas segmentifida
- Cycas semota
- Cycas seshachalamensis
- Cycas sexseminifera
- Cycas siamensis
- Cycas silvestris
- Cycas simplicipinna
- Cycas sphaerica
- Cycas sundaica
- Cycas szechuanensis
- Cycas taitungensis
- Cycas taiwaniana
- Cycas tanqingii
- Cycas tansachana
- Cycas terryana
- Cycas thouarsii
- Cycas tropophylla
- Cycas tuckeri
- Cycas vespertilio
- Cycas wadei
- Cycas xipholepis
- Cycas yorkiana
- Cycas zambalensis
- Cycas zeylanica