Floral ontogeny ofPedicularis(Orobanchaceae), with an emphasis on the corolla upper lip

Abstract

Pedicularis shows high diversity in its corolla form, however, its floral ontogeny has been rarely investigated. In particular, the development of the highly variable upper lip (galea), three broad morphological types of which (beakless and toothless, beakless and toothed, beaked) can be discriminated, remains unknown. We used scanning electron microscopy to investigate the early stages of floral ontogeny in two beaked species, Pedicularis gruina and P. siphonantha. To compare the developmental processes of the three galea types, three species for each type were investigated. Initiations of floral organs in Pedicularis are consistent. Sepal initiations are successive from the lateral-adaxial primordia, followed by the lateral-abaxial ones (these sometimes missing), then the mid-adaxial one (again sometimes missing). The stamens are initiated prior to the petals, or development of petal primordia may be retarded at the early stages in comparison with that of stamen primordia. Four stamen primordia are initiated simultaneously. The five petal primordia are initiated almost simultaneously. Development processes of the upper lip among the three galea types differ in the expansion rates and directions of the cells of the two lobes and these differences govern whether or not a beak and/or teeth are formed on the upper lip. The floral ontogeny of Pedicularis is close to that of Agalinis, which supports the molecular assignment. Floral monosymmetry of Pedicularis is established at the beginning of sepal initiation and is maintained until flowering. The development of the upper lip provides some clues to the evolution of beaked and/or toothed galeas in Pedicularis.

Towards a comprehensive phylogeny of the large temperate genus Pedicularis (Orobanchaceae), with an emphasis on species from the Himalaya-Hengduan Mountains

“…Short-tubed species can bear all three types of galea (beakless and toothless, beakless and toothed, and beaked), while all long-tubed species are beaked (only P. cyathophylloides has an obscure beak). Studies of development of the upper lip show that different expansion patterns of the two upper petals determine whether the galea will or not develop a beak or teeth [ 60 ]. The evolution of galea teeth shows high levels of homoplasy [ 21 ], but galea teeth are synapomorphic for the monophyletic series Lyratae , Rigidae and Reges .…”

Floral nectary morphology and evolution inPedicularis(Orobanchaceae)

“…Davis et al (1996) suggested that earlier formed floral organs could impose physical constraints on the morphology and size of the later derived nectary. In Pedicularis, nectary formation appears to be initiated after the establishment of the sepals, petals and ovary (Meier-Weniger, 1977;Cai, Liang & Wang, 2003;Yu et al, 2013a). Those species with an elongated nectary, e.g.…”

“…(1) short-tubed with beakless, toothless galea (i.e. the hoodlike upper lip); (2) short-tubed with beakless, toothed galea; (3) short-tubed with beaked galea; and (4) long-tubed with beaked galea (Li, 1951;Yu et al, 2008Yu et al, , 2013a (Fig. 1).…”

Phylogenetic approaches resolve taxonomical confusion in Pedicularis (Orobanchaceae): Reinstatement of Pedicularis delavayi and discovering a new species Pedicularis milliana

“…In addition, some publications just used the name “ P . siphonantha ” referring to this “long-tubed and purple-red species” in northwestern Yunnan [23–27]. …”