Spination is for many one of the most interesting features of plants in the Cactaceae Family. The endless variety is mind boggling to behold. From massively spined specimens such as the Stetsonia above to the fleathery plume like spines of Mammillaria plumosa, magnificence and beauty are to be found in almost every genera and species. Spines can come in all shapes, sizes and every color of the rainbow. Many times it is the dominate desirable feature of the plant.
     Spination likely evolved as a means of defense from grazing animals. Spines can also offer a defense from the searing sun especially those that have evolved almost hair like spines like some of the South American columnars. Many genera such as Ferocactus and Echinocactus are massively spined and animals give them a wide berth. Others such as some of the Gymnocaclyciums have spines that seem to encage the plant, protecting without being quite as offensive. But in some cacti the spination is harmless and seemingly more decorative. The spines of plants like Mammillaria theresae, Mammillaria plumosa and the like probably serve more for shade than anything else. Their harmless spination can offer no protection from foraging animals and can even be pleasant to the touch. In some cacti such as the Opuntias and especially the Cholla varieties, spination can also serves as an aid to reproduction. Animals brush by the fallen segments and they become temporarily stuck in their fur or flesh. Eventually the animal will work the segment free and deposit it farther away where it will often take root and become a completely new plant or colony.
     The images below were culled from many hundreds of photos in my collection. They are meant to illustrate the form, variety and colors of spination as well as some of the more unusual types of spines (in the miniature Mammilarias for example). I hope you enjoy :-)

The horned devil, Coryphantha elephantidens	Brutish, fierce and not to be messed with, Echinocactus ingens	The ruby red growing tip of an Echinocereus dasyacanthus var. rectispinus	Aptly named "Arizona Rainbow", Echinocereus rigidissimus
The beautiful spination of a golfball sized Ephithelantha micromeris	A macro of a button sized specimen of Ephithelantha micromeris	Aptly named for it's small size, an Escobaria minima	Another beautiful dwarf cactus with tiny hard spines, Escobaria vivapara var. kaibabensis
The cottony growth of an Espostoa ritterii	Beautiful but fierce, a gold spined Ferocactus latispinus	The normal red spined form of Ferocactus latispinus	Like candy canes, the new growth spines of Ferocactus macrodiscus
Aptly named "Spider Cactus", a Gymnocalycium denudatum	Another view of Gymnocalycium denudatum	The beautiful curly golden spines of Gymnocalycium euryplorum	A chocolate sculpture encaged in white bones, Gymnocalycium hossei
A closer view of Gymnocalycium hossei	A forest of felt covered black tipped horns, Gymnocalycium species nova	Another gnarly cage around an unknown Gymnocalycium	Impenetrable and beautiful Mammillaria gracilis
The horned spiders of Mammillaria huitzilopochtli	Mammillaria humboldtii covered in snowflakes	Only 1/8 inch across, the tassled spines of Mammillaria luethyi	Tiny but hard and sharp, the spines of Mammillaria parkinsonii
Aptly named for it's feathery spines, Mammillaria plumosa	The hard but harmless spines of Mammillaria saboae var .haudeana	Like little white spiders, the spines of Mammillaria schiedeana ssp. schiedeana	Mammillaria theresae covered in Sea Stars
New growth spines of a Myrtillocactus geometrizans	Another furry gold spined cactus, Oreocereus trollii	Magnificent red spines on this Stenocactus coptonogonus	Rippling ribs and spines of an unknown Stenocactus
Ribs and spines of another unknown Stenocactus	Purple bodied Sulcorebutia rauschii 'gold spine'	The papery but stiff spines of a Tephrocactus articulata ssp. papyracantha	Grooved centrals on a Thelocactus heterochromus
Tiny lace doilies on a Turbinocarpus valdezianus crest