anks ia ) ▁and ▁B .   a em ula ▁( W all um ▁B anks ia ) ▁placed ▁in ▁B .   sub ser . ▁B anks ia , ▁and ▁the ▁remaining ▁nine ▁species ▁placed ▁in ▁B .   sub ser . ▁C rat ist yl is . ▁The ▁latter ▁sub series ▁was ▁formally ▁defined ▁as ▁containing ▁those ▁species ▁with ▁" st out , ▁usually ▁monot on ically ▁cur ved , ▁smooth ▁styles , ▁and ▁seed ▁bodies ▁usually ▁with ▁sp ine - like ▁or ▁plate - like ▁processes ▁on ▁their ▁inner ▁faces ", ▁and ▁given ▁as ▁type ▁species ▁B .   men z ies ii ▁( Fire wood ▁B anks ia ). ▁The ▁sub series ▁name ▁comes ▁from ▁the ▁Greek ▁k rat ys ▁(" strong , ▁st ur dy ") ▁and ▁st yl os ▁(" style "), ▁in ▁reference ▁to ▁the ▁st out ▁style ▁and ▁pol len - present er ▁of ▁the ▁species ▁contained ▁there in . ▁ ▁The ▁pla cement ▁and ▁circ ums cription ▁of ▁B .   sub ser . ▁C rat ist yl is ▁in ▁Th iele ▁and ▁Lad iges ' ▁arrangement ▁may ▁be ▁summar ised ▁as ▁follows : ▁ ▁B anks ia ▁B .   sub g . ▁Is ost yl is ▁( 3 ▁species ) ▁B .   e leg ans ▁( inc ert ae ▁sed is ) ▁B .   sub g . ▁B anks ia ▁B .   ser . ▁T et rag ona e ▁( 4 ▁species ) ▁B .   ser . ▁Lind