Haplostele A type of protostele having a solid strand of stele with the xylem on the inside encircled by phloem, pericycle, and endodermis.

• 单中柱：原生中柱的一种类型，是由韧皮部、中柱鞘和内皮层包围着内方的木质部构成的实心中柱。