See Also

Frond

A frond is the breast Breast

The term breast, also known by the Latin [i] mamma in anatomy [i], refers to the upper ven ... 

- like structure of a fern Fern

A fern is any one of a group of about 20,000 species [i] of plant [i]s classified in the phylum or divis ... 

 or alga Algae

Algae encompass several different groups of usually relatively simple living organisms that capture lig... 

. The term is colloquially applied to the leaves of palm Arecaceae

Arecaceae , the Palm Family, is a family of flowering plant [i]s belonging to the monocot [i] ... 

s, cycad Cycad

Cycads are an ancient group of seed [i] plants [i] characterized by a large crown of compound leaves [i] ... 

s, and plants with pinnately compound leaves. A significant difference is that, unlike the leaves of the latter, fern fronds bear the reproductive structures of the sporophyte plant. Because many ferns grow fronds that are held more vertical than horizontal, the "upper" and "lower" surfaces of a frond are more correctly referred to as the adaxial and abaxial surfaces, respectively. A fern frond consists of a stipe, the stem supporting the blade, and the blade consists of both a laminar photosynthetic tissue and a rachis—that portion of the stem to which the laminar tissue is attached.

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A frond is the breast Breast

The term breast, also known by the Latin [i] mamma in anatomy [i], refers to the upper ven ... 

- like structure of a fern Fern

A fern is any one of a group of about 20,000 species [i] of plant [i]s classified in the phylum or divis ... 

 or alga Algae

Algae encompass several different groups of usually relatively simple living organisms that capture lig... 

. The term is colloquially applied to the leaves of palm Arecaceae

Arecaceae , the Palm Family, is a family of flowering plant [i]s belonging to the monocot [i]... 

s, cycad Cycad

Cycads are an ancient group of seed [i] plants [i] characterized by a large crown of compound leaves [i] ... 

s, and plants with pinnately compound leaves. A significant difference is that, unlike the leaves of the latter, fern fronds bear the reproductive structures of the sporophyte plant. Because many ferns grow fronds that are held more vertical than horizontal, the "upper" and "lower" surfaces of a frond are more correctly referred to as the adaxial and abaxial surfaces, respectively.

A fern frond consists of a stipe, the stem supporting the blade, and the blade consists of both a laminar photosynthetic tissue and a rachis—that portion of the stem to which the laminar tissue is attached. The blades of fern fronds may vary from being simple to being highly dissected, even "lace-like". If the leaf tissue is undissected, or the dissections do not reach to the rachis, the frond may be described as lobed or pinnatifid. Otherwise, the blade is compound and each large division of the laminar tissue arising from the rachis is called a pinna . The main vein or mid-rib of a pinna is known as a costa . Pinnae may be arranged along the rachis either directly opposite one another or alternating up the stem. The arrangement may change from the base of a blade to the tip, as in the example of Blechnum shown below .

Many ferns have pinnae that are divided two or more times, and the level of division of the fronds is termed pinnate , or twice-pinnate , or the like. Each secondary division is termed a pinnule, and its mid-vein, a costule. A few species of ferns with divided fronds are not pinnate Pinnate

Pinnate is a term used to describe feather [i]-like or multi-divided features arising from both sides of ... 

, but are palmate Leaf shape

In botany [i], the following terms are used to describe the shape of plant leaves [i]:
... 

 or bifurcate.


On some or all mature blades occur sporangia Sporangium

A sporangium is a plant [i] or fungal [i] structure producing and containing spore [i]s. ... 

, which bear the spore Spore

In biology [i], a spore is a reproductive [i] structure that is adapted for dispersion [i] ... 

s. The sporangia are clustered in a sorus Sorus

In fern [i]s, a sorus is a cluster of sporangia [i] on the edge or underside of a fertile frond [i] ... 

or "fruit dot". Associated with each sorus in many species is a membranous structure called an indusium: an outgrowth of the blade surface that may partly cover the sporangial cluster. Fronds also may bear hairs or scales, glands, and, in some species, bulblets for vegetative reproduction.

Each frond arises from the stem or rhizome Rhizome

A rhizome is, in botany [i], a usually underground, horizontal stem [i] of a plant [i] that o ... 

, which in most species is concealed in the ground or creeps along the ground surface. Growth of a fern frond differs from that of a leaf of a flowering plant Flowering plant

The flowering plants are a major group of land plant [i]s.... 

. The fern frond unrolls from a tightly-coiled structure called a "fiddle-head" .