Abstract
Eleven species of Andropogon produce single‐stamened flowers, and all but one of these species bear some cleistogamous flowers. Nine of the species, all diploid perennials, make up the Andropogon virginicus complex. Cleistogamy in the virginicus complex results from precocious maturation of the flowers, which leaves them confined within their spikelets at anthesis. Variation in flowering mode (expressed as mean % chasmogamy) is correlated significantly (P < 0.01) with variation in peduncle length (rs = 0.67), spikelet length (rs = 0.49), and anther length (rs = 0.69). The strength of the correlation (r = 0.94) between pollen grain number per anther and anther length makes the latter a good measure of pollen‐ovule ratios in the single‐stamened flowers of this group. Taxa with the highest frequency of cleistogamous flowering are also the most successful colonizers of disturbed habitats. It is suggested that cleistogamy is important in the reproductive isolation of the numerous, closely related subspecific taxa of the virginicus complex.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
