Fig. 4.

Metaphase in three major taxa of bryophytes showing similarity of spindles. Metaphase spindle consists of minipoles terminating in broad polar regions, as is typical of land plants. In all, γ-tubulin has moved into the spindle itself and all traces of special structures associated with spindle initiation have disappeared. (A–D) The liverwort R. hemisphaerica. Scale bar = 5 µm. (E–H) The moss P. pyriforme. Scale bar = 4 µm. (I–L) The hornwort P. laevis. Scale bar = 5 µm. (A, E, I) Microtubules; (B, F, J) γ-tubulin; (C, G, K) nuclei; (D, H, L) composite.