Habitats epiphytic

Brachytheciaceae (Goffinet et al 2001), and Okamuraea in Brachytheciaceae (Tsubotaet al., 2002). The short laminal cells, another important diagnostic character of Leskeaceae, also exhibit a tendency to associate with epiphytic habitats the epiphytic genera mentioned above all have laminal cells shorter than nonepiphytic representatives of the respective families. 

The objectives of this chapter are several first, to resolve phylogenetic relationships within the Ptychomniales using DNA sequence data second, to reconstruct ancestral character states within the Ptychomniales and third, to test whether the presence of dwarf males correlates to morphological characters and the epiphytic habitat. 

Tests of correlated evolution of dwarf males with the ranaining morphological features and the epiphytic habitat were conducted using Discrete (Pagel, 1999). This was accomplished by first fitting a model to the data in which the two characters were allowed to evolve independently. The likelihood of this model was then compared to the likelihood of a more complicated model in which the characters evolve in a correlated fashion, and a likelihood ratio was calculated between the dependent and the independent model to test if the more complicated model was a better fit to the data than was the model assuming independent evolntion. 

Likelihood Ratio Test Statistics (LRT) and Probabilities (p-Value) of Tests of Correlation of Dwarf Males with Morphological Characters and the Epiphytic Habitat... 

Pavia H, Carr H, Aberg P (1999) Habitat and feeding preferences of crustacean mesoherbivores inhabiting the brown seaweed Ascophyllum nodosum (L.) Le Jol. and its epiphytic macroalgae. 

Orchids exploit two broad types of habitats—terrestrial and epiphytic. Terrestrial orchids have their peren-nating tissues in the surface substrate of the ground, such as the soU or organic floor of a forest, or the surface sediment or peat of a wet meadow or bog. In contrast, epiphytic orchids use trees as a platform upon which to grow within the canopy. Epiphytic orchids do not obtain their moisture or nutrients from their host— they only use the tree as a physical substrate upon which to grow, either perched on a branch or as a climbing, vine-like plant. 

Besides frequently having orthotropous capsules, epiphytic pleurocarps possess several other sporophytic character states more often than species of other habitats. These include short setae, ovoid to cylindrical and straight capsules, round stomatal pores, lack of or a poorly developed separating annulus, rostrate lids, papillose lower exostome outer surface, reduced exostome primary... 

Taxonomically these families do not show an obvious close relationship (Fig. 1.1). They do have, however, two distinct features in common. Firstly, all the families are tropical or subtropical in origin and many of the CAM species have invaded arid regions. The CAM species occupy arid or locally dry niches. These include arid desert-type habitats and physiologically dry habitats such as encountered by epiphytes and plants existing in very rocky or shallow soils. Some, in fact, such as Dudleya may actually grow within rock wall faces. Secondly, most of those species which show CAM are either stem or leaf succulents, or fleshy or coreia-cous leafed plants such as the bromelid and orchid epiphytes (see Chap. 2.1). 

The CAM plants found in the 18 families studied are largely distributed along the tropics of Cancer and Capricorn and in the wet tropics in physiologically dry, epiphytic type habitats. Habitat and niche rather than phylogeny appear to be important. Hence, convergent evolution is apparently the explanation for the existence of the CAM photosynthetic pathway in these plants. 

There is no doubt that the storage of water by succulents represents an ecological adaptation, because succulents are xerophytes which occupy habitats where either precipitation occurs only periodically or soil water is generally not available (e.g., epiphytes) and periods of water deficiency are overcome with endogenous water reserves (see Chap. 6). 

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