Allen (2002) summarized the importance of various characters in Philonotis:
"Important gametophytic characters in the taxonomy of Philonotis
include perigonial form, sexuality, the position of papillae over the cell lumina,
leaf margin stance, costal length, and branching pattern. Sexuality and perigonial
form are characters of sectional importance. Section Philonotis consists
of dioicous mosses with enlarged and discoid perigonia, while section Philonotula
can be dioicous, synoicous, or autoicous with smaller, gemmiform perigonia. Papillae
position, leaf marginal stance, and costal length are important characters at
the species level, and unfortunately they tend to be quite variable. Papillae
position is perhaps the most important of these species-level characters. The
papillae can be projecting from the upper ends of cells, the lower ends of the
cells, from the center of the lumen or nearly smooth. As a rule those species
with papillae projecting only from the upper ends of cells are wildly variable
in the expression of this feature. Frequently it is only the lower to median leaf
cells that have papillae projecting from the lower ends, while the upper cells
have papillae projecting from the upper ends. Costa length varies from subpercurrent
to percurrent to variously excurrent. In general the value of this feature lies
in distinguishing the subpercurrent/percurrent/short excurrent forms from the
long excurrent forms... All species of Philonotis branch sparsely and irregularly,
but most species also have the tendency to have whorls of branches below the terminal
perichaetia."
Note for using the keys:
Species
of genus Philonotis show extreme seasonal, developmental and environmental
variability. Size of plants, leaf arrangement, density of tomentum, length of
excurrent part of costa, costa width and cell wall thickness are characters that
are to some extent plastic. Poorly developed plants can be undeterminable. Spring
innovations often bear atypical leaves difficult to key out. Leaves produced
in later parts of season on best-developed sterile unbranched stems are the best
for determination. Philonotis also produces lateral innovations that
have smaller, relatively narrow leaves with large, thin-walled cells and weakly
developed papillae that are variable in position; such leaves appear to be juvenile
in their morphology and they are difficult to key out. Spiral leaf arrangement
can be observed in stems of all European species. This feature is mentioned in
cases when it occurs regularly in fully developed plants. Size of cells in the
middle part of the leaf lamina in broadest part of leaf (but not the most basal
part) is measured. These cells and adjacent cells towards middle of the leaf are
the best for examination of papillae position. Papillae and mamillae intergrade
in most specimens of European Philonotis, the term 'papillae' is used ultimately
for both characters. Costa width is measured ca. 100-150µm above the leaf base
(so the sudden enlargement prior to stem attachment does not affect the measured
size). Marginal rows of cells bear usually papillae in both ends or in variable
position. Narrow margin recurvature is folded over 1-2 cells. Broad recurved margin
is more than 3 cells folded margin.
Allen, B., 2002: Moss
flora of Central America, Part 2. Encalyptaceae-Orthotrichaceae. - Monographs
in Systematic Botany from the Missouri Botanical Garden, 90: [i--viii] 1-699.
Buryová B. (1996): Rozšíření druhů rodu Philonotis v České republice. [Distribution
of Philonotis species in the Czech Republic]. - Ms., 86 p. Department of
Botany, Charles University, Prague. (Master thesis, in Czech)
Buryová B.
(2004): Morphological and genetic variation in selected species of the genus Philonotis
(Bartramiaceae, Bryopsida). - Ms., 101 p., Department of Botany, Charles University,
Prague. (PhD thesis, in English)
from B. Buryová, 2004
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