The plant morphologist goes further .
The plant morphologist discovers that the spines of cactus also share the same basic structure and development as leaves in other plants , and therefore cactus spines are homologous to leaves as well .
The plant morphologist goes further , and discovers that the spines of cactus also share the same basic structure and development as leaves in other plants , and therefore cactus spines are homologous to leaves as well .