<P> There are also spines derived from roots , like the ones on the trunk of the `` Root Spine Palms '' ( Cryosophila spp . ) . The trunk roots of Cryosophila guagara grow downwards to a length of 6 -- 12 cm , then stop growing and transform into a spine . The anatomy of crown roots on this species ( roots among the bases of the living fronds ) also alters during their life . They initially grow upwards and then turn down and finally they , too , become spinous . Lateral roots on these two types of roots , as well as those on the stilt roots on this species , also become spinous . Some authors believe that some of these short spiny laterals have a ventilating function so they are ' pneumorhizae ' . Short spiny laterals that may have a ventilating funcion may also be found on roots of Iriartea exorrhiza . There are also spines that function as pneumorhizae on the palm Euterpe oleracea . In Cryosophila nana ( formerly Acanthorhiza aculeata ) there are spine roots or root spines , some authors may prefer `` root spines '' if the length of the root is less than 10x the thickness , and `` spine roots '' if the length is more than 10x the thickness . Adventitious spiny roots have also been described on the trunks of dicotyledonous trees from tropical Africa ( e.g. Euphorbiaceae , as in Macaranga barteri , Bridelia micrantha and B. pubescens ; Ixonanthaceae , Sterculiaceae ) , and may also be found protecting perennating organs such as tubers and corms ( e.g. Dioscorea prehensilis - Dioscoreaceae - and Moraea spp . - Iridaceae - respectively ) . Short root spines cover the tuberous base of the epiphytic ant - plant Myrmecodia tuberosa ( Rubiaceae ) , these probably give protection to ants which inhabit chambers within the tuber as they wander over the plant 's surface . ( Jackson 1986 and references therein ) . In many respects the pattern of spine formation is similar to that which occurs in the development of thorns from lateral shoots . ( Jackson 1986 and references therein ) . </P>
<P> There are also spines derived from roots , like the ones on the trunk of the `` Root Spine Palms '' ( Cryosophila spp . ) . The trunk roots of Cryosophila guagara grow downwards to a length of 6 -- 12 cm , then stop growing and transform into a spine . The anatomy of crown roots on this species ( roots among the bases of the living fronds ) also alters during their life . They initially grow upwards and then turn down and finally they , too , become spinous . Lateral roots on these two types of roots , as well as those on the stilt roots on this species , also become spinous . Some authors believe that some of these short spiny laterals have a ventilating function so they are ' pneumorhizae ' . Short spiny laterals that may have a ventilating funcion may also be found on roots of Iriartea exorrhiza . There are also spines that function as pneumorhizae on the palm Euterpe oleracea . In Cryosophila nana ( formerly Acanthorhiza aculeata ) there are spine roots or root spines , some authors may prefer `` root spines '' if the length of the root is less than 10x the thickness , and `` spine roots '' if the length is more than 10x the thickness . Adventitious spiny roots have also been described on the trunks of dicotyledonous trees from tropical Africa ( e.g. Euphorbiaceae , as in Macaranga barteri , Bridelia micrantha and B. pubescens ; Ixonanthaceae , Sterculiaceae ) , and may also be found protecting perennating organs such as tubers and corms ( e.g. Dioscorea prehensilis - Dioscoreaceae - and Moraea spp . - Iridaceae - respectively ) . Short root spines cover the tuberous base of the epiphytic ant - plant Myrmecodia tuberosa ( Rubiaceae ) , these probably give protection to ants which inhabit chambers within the tuber as they wander over the plant 's surface . ( Jackson 1986 and references therein ) . In many respects the pattern of spine formation is similar to that which occurs in the development of thorns from lateral shoots . ( Jackson 1986 and references therein ) . </P>
thorns on plants is a feature of trees in
thorns on plants is a feature of trees in
tropical Africa
tropical Africa