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The fertile leaves appear first; their green color slowly becomes brown as the season progresses and the spores are dropped. The spore-bearing stems persist after the sterile fronds are killed by frost, until the next season. The spores must develop within a few weeks or fail. The Osmundastrum cinnamomeum fern forms huge clonal colonies in ...
Transplants are rarely successful, and the development of mature plants from spores is very slow (taking perhaps 20 years). They can be grown with frequent application of weak fertilizer solution under bright light, high humidity, and year-round moderate temperatures in greenhouses, growth chambers, and laboratories. [ 11 ]
The term "fern ally" included under Pteridophyta generally refers to vascular spore-bearing plants that are not ferns, including lycopods, horsetails, whisk ferns and water ferns (Marsileaceae, Salviniaceae and Ceratopteris). This is not a natural grouping but rather a convenient term for non-fern, and is also discouraged, as is eusporangiate ...
The rhyniophytes included "protracheophytes", which were precursors to vascular plants (e.g., Horneophyton, Aglaophyton); basal tracheophytes (e.g., Stockmansella, Rhynia gwynne-vaughanii); and plants allied to the lineages that led to the living club-mosses and allies as well as ferns and seed plants (e.g., Cooksonia species).
Prothallus of the tree fern Dicksonia antarctica (note new moss plants for scale) Spore-bearing plants, like all plants, go through a life-cycle of alternation of generations. The fully grown sporophyte, what is commonly referred to as the fern, produces genetically unique spores in the sori by meiosis.
In flowering plants, the gametophytes are very reduced in size, and are represented by the germinated pollen and the embryo sac. The sporophyte produces spores (hence the name) by meiosis, a process also known as "reduction division" that reduces the number of chromosomes in each spore mother cell by half. The resulting meiospores develop into ...
It is a small, delicate, low-growing plant. Its perennial sterile stems are short, slender and irregularly branched reaching up to 15 cm in length. They creep along the ground but usually turn upwards near the tip. They have small, pointed, triangular leaves about 1–2 mm long, each bearing a ligule on its upper surface near the base. [3]: 7
Zosterophyllum is a vascular plant. The axes (stems) are naked, lacking leaves or outgrowths ("enations"). The axes (stems) are naked, lacking leaves or outgrowths ("enations"). When branching occurs, the branches are either isotomous (equally sized) or pseudomonopodial (one branch is larger than the other but still clearly involves division of ...