Why are the seeds of this species difficult? Some species of the Cyperaceae family can produce a high proportion of empty seeds, which collectors and curators must take account of. The seeds may have physiological dormancy.
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This species most probably has Orthodox seeds - dry to 15-20% eRH and store at -20ºC, or as cool as possible.
Germinate on agar, germination paper or sand under constant temperatures of 20, 25 or 30ºC, or using alternating temperature regimes of 30/15, 35/20 or 40/25ºC (with an 8/16hr photoperiod), depending on local environmental conditions. Perform a cut-test on any seeds that have not germinated, to check for empty seeds. All empty seeds are non-viable in germination tests.
The seeds of this species may be Physiologically Dormant (based on other species in the same genus). If germination is low, this type of seed dormancy can be overcome by mimicking the seasonal patterns of the species' native habitat. Use a moist pre-chill or pre-heat treatment (depending on local climatic conditions) or a dry after-ripening treatment, before germinating the seeds on agar, germination paper or sand at their optimum temperature. If this does not work, you can perform delicate surgery to enable the embryo to grow. Excise the tissue near the root tip.
The production of empty seeds is common in non-domesticated species of the Cyperaceae. Empty seeds may have a normal seed coat but an absent or under-developed embryo, or limited storage tissue.
Accepted name: Cyperus polystachyos Rottb.
Synonyms: Cyperus brizaeus J. Presl & C. Presl, Cyperus filicinus Vahl, Cyperus fugax Liebm., Cyperus gatesii Torr., Cyperus microdontus Torr., Cyperus odoratus L., Cyperus olidus Vahl, Cyperus paniculatus Rottb., Cyperus polystachyos var. hahnianus (Boeckeler) Kük., Cyperus polystachyos var. leptostachyus Boeck., Cyperus polystachyos var. paniculatus C.B. Clarke, Cyperus polystachyos var. texensis (Torr.) Fernald, Cyperus texensis (Torr.) Steud., Pycreus polystachyos (Rottb.) P. Beauv., Pycreus polystachyos subsp. holosericeus (Link) T. Koyama
References and Links
- Black, M., Bewley, J.D. and Halmer, P. (2006). The Encyclopaedia of Seeds: science, technology and uses. CAB International, UK.
- Food and Agriculture Organization of the United Nations and International Plant Genetic Resources Institute (1994). Genebank Standards. FAO/IPGRI, Rome, Italy.
- AFPD (African Flowering Plants Database) - Conservatoire et Jardin Botaniques de la Ville de Genève, Switzerland, and South African National Biodiversity Institute, Pretoria, RSA: Cyperus polystachyos.
- SID (Seed Information Database) - Royal Botanic Gardens, Kew, UK: Cyperus polystachyos var. polystachyos.
- Tropicos - Missouri Botanical Garden, USA: Cyperus polystachyos.