Glossary of terms used in cycad systematics - Cycad Specialist Group
Glossary of terms used in cycad systematics - Cycad Specialist Group
Glossary of terms used in cycad systematics - Cycad Specialist Group
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Walters & Osborne – <strong>Cycad</strong> Classification: Concepts & Recommendations, Appendix 2 6<br />
convergence. Evolutionary process where dissimilar organs or organisms show strong superficial<br />
similarities.<br />
coralloid root. Club-shaped apogravitropic (apogeotropic) root with the potential for host<strong>in</strong>g<br />
symbiotic Cyanobacteria.<br />
coriaceous. Leathery <strong>in</strong> texture, as for the leaflets <strong>of</strong> many <strong>cycad</strong> species.<br />
corruptel. Kernel <strong>of</strong> a corruptule (Grobbelaar, 2002).<br />
corruptule. Unfertilised ovule that is superficially <strong>in</strong>dist<strong>in</strong>guishable from a true seed (Grobbelaar, 2002).<br />
See also omnule.<br />
CSG. <strong>Cycad</strong> <strong>Specialist</strong> <strong>Group</strong>, a conservation-based group with<strong>in</strong> the IUCN.<br />
cuneate. Wedge-shaped and attached at the narrow end.<br />
Curculionidae. Weevil family <strong>of</strong> <strong>in</strong>sects.<br />
cuticle. In plants, the outer waxy layer <strong>of</strong> an epidermis, compris<strong>in</strong>g ma<strong>in</strong>ly cut<strong>in</strong> with lesser amounts <strong>of</strong><br />
overlay<strong>in</strong>g waxes and polysaccharides.<br />
cut<strong>in</strong>. Complex polymeric mixture <strong>of</strong> fatty acids and phenolic compounds; the ma<strong>in</strong> component <strong>of</strong> a<br />
plant cuticle.<br />
Cyanobacteria. <strong>Group</strong> <strong>of</strong> bacteria capable <strong>of</strong> photosynthesis, previously known as blue-green algae,<br />
found <strong>in</strong> coralloid roots <strong>of</strong> <strong>cycad</strong>s.<br />
<strong>Cycad</strong> Action Plan. Series <strong>of</strong> proposals for <strong>cycad</strong> conservation drafted by the CSG.<br />
<strong>Cycad</strong>ales. Gymnosperm plant order conta<strong>in</strong><strong>in</strong>g all extant and ext<strong>in</strong>ct <strong>cycad</strong>s.<br />
<strong>cycad</strong>s. Members <strong>of</strong> the plant order <strong>Cycad</strong>ales.<br />
cycas<strong>in</strong>. Toxic MAM glycoside found only <strong>in</strong> <strong>cycad</strong> tissue; methylazoxymethanol-ß-D-glucopyranoside.<br />
See also macrozam<strong>in</strong>.<br />
cymbiform. Boat-shaped.<br />
cytology. Study <strong>of</strong> the structure, physiology and reproduction <strong>of</strong> cells.<br />
DAF. DNA Amplification F<strong>in</strong>gerpr<strong>in</strong>t<strong>in</strong>g, a technique <strong>used</strong> <strong>in</strong> DNA analysis.<br />
decumbent. Of stems, ly<strong>in</strong>g along the ground but turn<strong>in</strong>g upwards distally. See also procumbent,<br />
prostrate.<br />
decurrent. Extend<strong>in</strong>g basipetally from the po<strong>in</strong>t <strong>of</strong> <strong>in</strong>sertion, as for Lepidozamia leaflets where the<br />
leaflet base extends downwards along the rachis.<br />
dehiscence. Ruptur<strong>in</strong>g process where the contents <strong>of</strong> a plant structure are released, as <strong>in</strong> pollen shedd<strong>in</strong>g.<br />
deltran optimization. Optimization technique <strong>used</strong> <strong>in</strong> cladistics, based on ‘delayed transformation’ and<br />
favour<strong>in</strong>g <strong>in</strong>dependent ga<strong>in</strong>s rather than acquisition and reversal. Cf. actran optimization.
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