Staminode inner

Functional stamens usually five or one, but if six then the inner perianth is zygomorphic the staminodes... 

Fig 3.11 Selected floral characters mapped on the backbone tree of Doyle and Endress (2010) with fossil Cohongarootonia hispida (PP53716) included. (A) Presence of inner staminodes. (B) Presence of androecial appendages. 

Endress, P. K. (1984). The role of inner staminodes in the floral display of some reUc Magnoliales. Plant Systematics and Evolution, 146, 269-282. 

Fig 12.2 Mature flowers of Afa/oofeowaca. (A)-(B)N. imperiaUs (C)-(F)JV. vogelii. (A)-(D) Distal and lateral view of flower at anthesis. (E) detail of (C) central part with staminodes, stamens and ovary. (F) Floral bud prior to anthesis. Note the petals opening along the midribs. Af, fertile stamen As, sterile stamen Ci, inner corona Co, outer corona Ct, corona threads St, stylar lobe. Scale bars = 10 mm. For colour illustration see plate section. 

The androecium is highly complex, consisting of an inner tier of fertile halfstamens alternating with staminodial appendages, an intermediate tier of erect staminodes and an outer tier of refiexed filiform staminodes. Two possibilities can explain the existence of paired half-anthers in the inner tier ... 

The inner tier represents two alternating whorls, one of paired stamens and one of paired staminodes. 

---