Reproductive ecology of the Australian herb Trachymene incisa subsp.incisa (Apiaceae)

Abstract

Abstract. Within the Apiaceae, subtle variation in reproductive characters such as dichogamy, pollinator specificity and umbel density may cause cryptic specialisation and be responsible for the diversity of life histories and gender expression in the family. To address the paucity of information for Australian species we investigated the reproductive ecology of the native perennial herb, Trachymene incisa Rudge subsp. incisa. T. incisa exhibits protandry within flowers and umbels; however, an overlap of 3 days in male and female phases among umbels of consecutive orders permits geitonogamous pollination. There are 72 ± 2.0 (n = 74) white flowers per umbel and nectar is presented during the male and female phases. Apis mellifera appears to be the main diurnal pollinator. The pollen:ovule ratio is 1902:1, indicating that T. incisa is a facultatively xenogamous species. The long phase of pollen presentation and the low natural seed set of about 45% implies that many flowers are functioning as pollen donors only. Controlled pollination experiments showed that self-pollen led to lower seed set than cross, open and supplemental applications. Early and late-produced cohorts differed in days to emergence but not in seed mass or final percentage emergence.

Reproductive biology and reproductive output assessment in natural and introduced subpopulations of Apium bermejoi, a ‘Critically Endangered’ endemic plant from Menorca (western Mediterranean)

“…Our bagging experiments indicate that this species can develop viable seeds by selfing, as has been reported for other Apiaceae species (Lindsey 1982, Davila and Wardle 2002), and seeds from selfing exhibited similar final germination to control seeds. Although both the percentage of fructified umbels and the fruit set are lower in ‘bagged with muslin’ plants than in ‘open‐pollinated’ plants, our experimental results reveal that A. bermejoi is self‐ compatible.…”

“…The umbel arrangement and umbel maturation contrast with those of other well‐described Apiaceae species. For example, Trachymene incisa is protandrous at the flower and inflorescence levels but nonetheless, exhibits an overlap between the male and female phases of umbels of consecutive orders (Davila and Wardle 2002). In the case of Naufraga balearica , the marked protandry at both the flower and inflorescence level and the sequence of development and inflorescence maturation, which occurs simultaneously at different stolons, provide clear evidence that cross‐pollination is being promoted in this species (Cursach and Rita 2012).…”

Nectaries and male-biased nectar production in protandrous flowers of a perennial umbellifer Angelica sylvestris L. (Apiaceae)

“…Our study species produced nectar during both flower sexual phases, as commonly found in other dichogamous species of Apiaceae (Koul et al 1989(Koul et al , 1993Davila and Wardle 2002;Langenberger and Davis 2002;Pérez-Bañón et al 2007;Zych 2007). Differences in nectar sugar concentration between years (a decrease noted particularly in female stage) were probably caused by weather conditions.…”

Pollen morphology and the flower visitors of Chaerophyllum coloratum L. (Apiaceae)

“…From the pollination point of view, C. coloratum, being an aromatic plant, is most appealing to Apidae, followed by Syrphidae, and to a lesser extent to carrion fl ies. According to the present study, the most frequent visitor to Chaerophyllum fl owers was the honeybee, which was also registered as an important pollinator of some other Apiaceae, such as Trachymene incise (Davila and Wardle 2002) and Carum carvi (Langenberger and Davis 2002b), but not in the case of Heracleum sphondylium (Zych 2006). Unlike Zych (2006) who noticed a few butterfl ies from the families Nymphalidae, Papilionidae and Pierideae visiting Heracleum fl owers, the present study mentions only moths with short mouthparts feeding on Chaerophyllum fl owers.…”