Biology lecture 3/20/151. Bryophyta: Class sphagnidae- Cytological/morphological specializations: water retention- Ecological importance: bog/peat formation2. Phylum Hepatophyta- Unique gametophytesClass sphagnidae- Single genus: sphagnum ~200 sps.- Covers 2% of the earth’s terrestrial surface- Very significant effects on nutrient cycling, biodiversity, etc.- Specialized for water uptake/retentionSphagnum growth form: hammocks, cushions; usually dominate siteHyaline cells: water holding cells, hollow and dead at maturitySphagnum bog (peat land)- Peat: partially decomposed plant tissues that are mostly sphagnum - Sphagnum can hold 20 times its dry weight in water while cotton can hold four times its dry weight- Creates bog/wetland conditionsPeatland/bog substrates are- Hydric- Acidic- Cold- Partially anaerobicRetard decomposition, nutrient cycling is bad news for rooted plantsPeat is a renewable energy source20% of electrical power in Ireland is from peat combustionPhylum Hepatophyta: Liverworts- Gametophyte thalloid or leafyLeafy liverworts look like mosses but are very different2 thalloid liverworts: marchantia and RicciaMarchantia sexual reproductionAntheridiophores: produce antheridia in a disc-shaped regionArchegoniophores: stalked palm-tree shaped structures that has archegonia on the underside of their
View Full Document
Unlocking...