@article {299,
	title = {Inflorescence and floral morphology in Tofieldia (Tofielidaceae) compared with Araceae, Acoraceae and Alismatales s.str.},
	journal = {Bot. Jahrb. Syst.},
	volume = {124},
	number = {3},
	year = {2003},
	month = {October 27, 2002},
	pages = {255-271},
	abstract = {In recent time the taxonomic relationship of Tofieldiaceae was revised due to molecular data. Together with Araceae s.str. Tofieldiaceae was included in Alismatales. In order to establish whether morphological data agree wit molecular ones, inflorescence and flower structure of Tofieldia were studied. Alismatales s.str. and Tofieldiaceae have similarities in gynoecium and androecium structure, but these features are insufficient to confirm the placement of Tofieldiaceae into Alismatales s.l. We found additional features shared by Tofieldia and some of Alismatales s.str., Araceae and Acoraceae. In Tofieldia, as well as in species of Araceae with trimerous flowers, the outer median tepal occupies adaxial position (in  the majority of monocots its position is abaxial). Tofieldiaceae is characterised by presence of the structure, usually described as calyculus, at the pedicel. The calyculus typically consists of three free or connate scales. Calyculus of Tofieldiaceae resembles the "spathe" of Hydrocharitaceae and (pseudo)whorls of bracts in Alismataceae. However, the calyculus exhibits also important features of perianth whorl. The situation may be compared to some Alismatales where an exact "boundary" between structures of "flower" and "inflorescence" is often scarcely recognisable. A tendency to produce organs combining features of subtending bract and the first median abaxial phyllome on the pedicel is shared by Tofieldia pusilla, Acorus, Juncaginaceae, and some Potamogetonaceae. Our data support inclusion of Tofieldiaceae into the expanded order Alismatales.},
	author = {Remizova, Margarita and Sokoloff, Dmitry}
}
@article {103,
	title = {Non-tetrasporangiate stamens in the angiosperms: structure, systematic distribution and evolutionary aspects},
	journal = {Bot. Jahrb. Syst.},
	volume = {112},
	number = {2},
	year = {1990},
	pages = {193-240},
	abstract = {Derivations from the normal tetrasporangiate, dithecal pattern of angiosperm stamens are presented in a comparative study of numerous taxa and a literature survey. Regularly occuring polysporangiate stamens (with more than 4 sporangia) are known from 18 families, all dicotyledons, regularly occurring disporangiate stamens from c. 50 families. Most polysporangiate stamens have retained thecal organization with two longitudinal dehiscence lines: each of the 4 pollen sacs is simply transversally and sometimes also longitudinally subdivided into numerous sporangia. Thecal organization is lost in some Viscaceae, Polyporandra (Icacinaceae), and Mitrastemonaceae, where each sporangium individually dehisces by a pore, and in Rafflesia, where all sporangia merge into one large pore. These deviating stamen forms are often correlated with specialized pollination biology: athecal polysporangiate anthers with pollen presentation in mucilaginous masses through pores and fly pollination; dithecal disporangiate anthers with (1) also pollen presentation in mucilaginous masses through relatively small openings and often fly pollination, (2) precise secondary pollen presentation on the gynoecium, (3) cleistogamy, (4) opening with valves. In these cases efficient wide gaping of 2 mirror-symmetrical halves of each theca is not possible. The biological context and the systematic distribution strongly support the hypothesis that the cohesiveness of the basic dithecal, tetrasporangiate pattern is at least partly due to functional constraints at the time of pollen release from the mature anthers.},
	keywords = {angiosperms, non-tetrasporangiate stamens},
	author = {Endress, Peter K. and Stumpf, Susanne}
}
