This section is from the book "On British Wild Flowers Considered In Relation To Insects", by John Lubbock. Also available from Amazon: Nature Series On British Wild Flowers Considered In Relation To Insects.
This order contains two British genera; Plantago and Littorella.
Plantago, the common Plantain, has small, hermaphrodite flowers in heads or spikes on a leafless peduncle. The sepals are four; the corolla has four lobes; the stamens are four, alternating with the petals, and very long; the style is long, simple, and hairy. This genus offers several interesting peculiarities.
Plantago major is proterogynous, and according to Axell, as I have already mentioned (ante, p. 10), is wind-fertilised, which, however, is not invariably the case in other species.
In PL lanceolata, Delpino has observed three different forms: Firstly, a form with a strong and high stalk; white and broad anthers. This he says is entirely wind-fertilised.
Secondly, one with a less elevated stalk, and less exclusively anemophilous. On it he observed a species of Halictus, which endeavoured to collect pollen. The plant is, however, so little suited to this, that most of the pollen fell to the ground.
Thirdly, a dwarf variety, with shorter stamens. This form was visited by several species of bees and is intermediate between wind-fertilisation and insect-fertilisation. Muller also has observed two varieties of this species; one tall and long-eared, the other shorter and smaller; both of them were visited by insects. P. lanceolata is proterogynous.
Plantago media is also proterogynous, though less so than P. lanceolata. It is more frequently visited by insects, having a slight scent, and stamens with pink filaments. Nevertheless, it appears to be generally fertilised by wind.
According to Darwin, several North American species are dimorphous (Proc. Linn. Soc. v. vi., 1862, p. 95), and Kuhn states that some have also cleisto-gamous flowers.
Fig. 119. - chenopodium bonus-henricus.