Comparative phenology and floral patterns in Larrea species (Zygophyllaceae) in the Monte desert (Mendoza, Argentina)

Breeding system of Bulnesia retama (Gillies ex Hook & Arn.) Gris. (Zygophyllaceae) in the Central Monte Desert (Mendoza, Argentina)

“…A similar phenological pattern was also observed in three closely related species of Larrea in Ñ acuñ án and in the piedmont near Mendoza City (Rossi et al, 1999).…”

“…1) that could have been favorable for further flowering. Nevertheless, we did not observe any subsequent bloom in B. retama nor in L. cuneifolia, a well-known opportunistic bloomer (Rossi et al, 1999). The basic pattern and development of Bulnesia flowers is very similar to that in L. divaricata and L. nitida (Rossi et al, 1999).…”

“…Nevertheless, we did not observe any subsequent bloom in B. retama nor in L. cuneifolia, a well-known opportunistic bloomer (Rossi et al, 1999). The basic pattern and development of Bulnesia flowers is very similar to that in L. divaricata and L. nitida (Rossi et al, 1999). The main difference was observed at stage 3, where petals do not rotate 901 and, therefore, stamens of the inner cycle are not protected by them.…”

“…The reproductive growth in B. retama could be a response to rainfall events, a common pattern observed in Larrea species ( Barbour et al, 1977;Solbrig & Yang, 1977;Ackerman et al, 1980;Kemp, 1983;Bowers & Dimmit, 1984;Rossi et al, 1999). Larrea cuneifolia, which co-exists with B. retama in the Ñ acuñ án Biosphere Reserve, showed a faster response to rainfall events, flowering 15-20 days earlier than B. retama (Rossi et al, 1999). During the study season, there were several summer rainfall events in Ñ acuñ án (i.e.…”

“…At stages 3 and 4, when the anthers release pollen, facilitated selfing as well as cross-pollination may occur due to pollinator activity, although autonomous self-pollination could also be possible (Lloyd & Schoen, 1992). Regarding this particular dichogamy mechanism, Bulnesia and Larrea species can be considered as incompletely protogynous (Lloyd & Schoen, 1992;Rossi et al, 1999). It is important to point out that similar morphological and phenological features of flowers in the related species of Bulnesia and Larrea might indicate phylogenetic constraints in the development and function of flower structures.…”