Fig. 2.

Early floral development in Streptochaeta, Elegia, and Joinvillea. (A–D) Streptochaeta spikelet equivalent development. (A) Mature spikelet equivalent with anthers emerging from the overlapping whorl of bracts X–XII, which are distinct in shape and size from the pointed bracts VII–IX. (B) Early floral development showing the long-awned bract VI, initiation of the “outer tepal” bracts VII–IX, one of the “inner tepal” bracts X–XII, as well as stamen (St) and carpel primordia. (C) The entire spikelet equivalent was detached from the inflorescence, the large enclosing bract VI was removed, and the flower was viewed from behind. Three stigmas are emerging from the overlapping whorl of bracts X–XII. Outside of this whorl, two of the bracts from the VII–IX whorl are developing their pointed tips, whereas the third apparently has aborted. (D) Later stage flower dissected from the inflorescence as in C showing the distinct development of the pointed outer tepal whorl VII–IX and the overlapping inner tepal whorl X–XII. (E–H) Elegia floral development. (E) A mature inflorescence containing flowers subtended by bracts just before anthesis. Labeled flower has the bract removed, showing that the inner tepals (IT) are longer than the outer tepals (OT) and each is morphologically distinct. (F) Young floral meristem with one outer tepal removed showing the initiation of inner tepal and St primordia. (G) Maturing flower showing hooded outer tepals. (H) Same as in G but with two outer tepals removed, showing the inner tepals as more laminar in shape than the young outer tepals in F and G. (I–L) Joinvillea floral development. (I) Mature flower showing the apparently similar morphology of the inner and outer tepals. (J) Early floral development clearly showing characteristic monocot floral morphology. (K) Later developmental stage showing distinct shape of the inner and outer tepal whorls. (L) Close view of the inner tepal in K showing flat broad triangular shape with a papillate margin as opposed to the narrowly pointed, curved outer tepal with a smoother margin.