Beyond Fern Fronds

Fig. 1   Fern fronds

A fern that has a flower is not a true fern and anything that resembles a flower on a fern is not a true flower. Ferns are not flowering plants but they are capable of reproduction through spores. The purpose of this article is to point out where this flowerless-reproduction takes place.

New fronds on ferns start out plain green (Fig. 1).  While some fronds are sterile, some are fertile for reproduction which can be differentiated by inspecting the under-side of the fronds as they begin to develop sori - the reproductive structure in ferns (Fig. 2).   

The sori  start out as rows of two dimentional dots (Fig. 2) and as they mature they turn increasingly three-dimensional resulting in an embossed appearance on the fronds. At this point, the sori are enclosed in a thin flap of tissue called indusium.  

Fig. 2.  Sori (singular: sorus) on the underside of  fertile fern fronds.

The indusium at first covers, the entire sorus (Fig.2).  However, as the sori mature, the indusia slowly recede to unveil the growing sporangia (Fig. 3) - each sorus containing clusters of sporangia. Eventually, the and finally detaches from the sorus leaving a velvety house of spores (Fig.4). 

Fig. 3   Indusium slowly revealing the sporangia as they mature.

Sporangium  (Fig. 4) is a receptacle in which asexual spores are developed.  Ferns are flowerless and seedless plants - therefore, they do not undergo sexual fertilization where a male cell unites with a female cell to form a new embryo.  Instead, they have sporangia that are like tiny packages containing multitudes of spores - all potentially capable of cell division to produce a multi-cellular organism - a new plant.  Minute as they are, spores are designed to survive and dispersed - they remain viable for a long time until favorable conditions are met.

Fig. 4    Sporangia all ready for dispersal.

Now that we know about fertile fern fronds that give rise to aggregates of sori that hold the sporangia which are the vessels that contain the spores, we can say that the fronds are not ordinary leaves.  Unlike the leaves of flowering plants which function mainly as sites for photosynthesis, the fern fronds perform dual functions - photosynthetic and reproductive. 

Breathing Plants



Fig. 1  Recovering ferns.  



Plants are not breathing organisms.* But why do some of us treat them as if they are hamsters or cats? We just can't throw plants away even if we don't need them anymore.  So we put them in a new but less conducive shelter in hope of future adoption.  Well, these plants (Fig.1) are like those.  They are no longer good for that corner in the garden but I still want to keep them.  They have been uprooted and planted in small containers.  The recovery will be slow but one day they will be lush once more and who knows, someone might be interested to have them. 



Fig. 2  Saved Schlumbergera stem now blooming.  



There are plants everywhere in my garden that are not supposed to be there.  Spider plants, Christmas cacti (Fig. 2), and mints are growing in small pots here and there.  Why I keep them is still a question.  Could it be that my subconscious belief tells me that these plants are breathing - that to get rid of them could be murderous?  I refuse to admit that I am in fact a hoarder of plants.



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*One might argue that plants also breathe through their stomata - but that's not breathing because there are no lungs involved.  It's called gas exchange. :)

Save your plants only if you know that they will be useful to you or someone else in this lifetime.