Thursday, December 30, 2010

Tenderness and fragility: Anogramma leptophylla

The annual cycle Anogramma leptophylla fern is tenderness in capital letters, tenderness of tender, fragile, tiny, fleeting, transparent, light weight. Its life does not usually exceed 8 months since the spore germinates to death the fern.

I will tell the life cycle of this wonder of nature. Start at the beginning, the dispersal of spores per sporangium at the end of spring.

Sporangium of Anogramma leptophylla after spore dispersal. Crosslinked structure is the transparent bag, traditional style of the family of Hemionitidaceae and two spores that have been attached. The bag, which acts like a womb, is torn to permit the release of spores. The ring of cells has two functions. While spores are being formed placenta acts as a feeding them and surrounding them in a protective embrace. At the same time accumulating energy in the form of tension, so that, once the spores are ripe and environmental circumstances are favorable, the ring bursts with unusual force, tearing the transparent bag containing the spores and they shoot out as far as possible in search of new territories.

Spores of Anogramma leptophylla with a beautiful dark garnet color and quite large. The strength of the sporangium ring that acts as a catapult, with the wind and rain, leading to the spores as far as possible. Since its dispersion coincides with the end of the spring, once dispersed, are dormant holding the torrid heat and drought of the long summer months.

 
If they are lucky and have fallen on a wet and shaded substrate, with the first rains of autumn germinate and give rise to a gametophyte that is big enough in kidney or heart form of a dark green color. If autumn rains continue, the gametophytes produce gametes: female oosphere and male anterozoides. Swimming in soil moisture, attracted by chemotaxis by malic acid secreted by a mature oosphere, swimming flagellates anterozoides are looking for the source of the pheromone that both attracts and fertilize once reached. The fertilized oosphere emits a small frond, the sporophyte or true fern and we have a new Anogramma leptophylla. In the photo shows a dark green gametophyte with a small frond of lighter color, which comes directly from the fertilized oosphere found in the archegonium of the gametophyte.

In this picture are a group of gametophyte or prothallus on a base of moss, which acts like a sponge and absorbs moisture from morning dew, facilitating the development of Anogramma. We also see a new or sporophyte frond that has sprung from a fertilized oosphere. Picture taken in October at a wall patch Sóller Valley.

Here are several true fern sporophytes or a little more developed, with the sterile fronds, which accumulate energy and nutrients, then to issue one or two fertile fronds with sporangia very vigorous and upright. Picture taken in December in the Torrent de Pareis on the northwest coast of the island of Mallorca.

Young Anogramma leptophylla with sterile fronds well developed, growing in a crack of a rock accompanied by a Sherardia arvensis.

Fully developed vigorous specimen with the sterile fronds at the bottom and a long, fertile fronds erect to 20 cm., photographed at Caldeira do Faial in the Azores Archipelago in mid-May.

Several Anogramma leptophylla on a base of liver in a crevice of a rock, sharing the habitat with several Sedum and a pair of Campanula erinus. They are dry and sterile fronds at the base. Photograph taken in May at the Natural Park Sierra de Grazalema in Cadiz.

 
Vigorous specimen growing in the intense darkness of a laurel forest from the beautiful Forest of the Tiles of the Isla de la Palma. In this case the growing fronds pendulous looking for the little light that filters through the treetops. Photograph taken in early May.

Specimen of Soller Valley that grows between the stones of the wall of a terrace. The fertile frond is about 15 cms. and its underside is filled with spores about to be dispersed. Picture taken in late April.

Underside of the frond above with mature sporangia about to disperse the spores. (Double click on the photo to enlarge)

Beautiful picture of the sporangia on the underside of a fertile frond Anogramma leptophylla.

Sporangia themselves earlier in detail. Sporangia can be seen in three colors: the reds are immature and will mature in the coming days, blacks are at their optimum ripeness and are "giving birth" spores contained in a transparent bag, which is torn to unwind sharply ring surrounding the sporangium and dispersed the spores as a small catapult as far as possible. Finally, transparent (which are green) are the uterus and birthed, the empty bags remaining after spore dispersal.

Once you've managed to complete their life cycle, leaving the earth the seeds of the next generation, Anogramma leptophylla going to acquire a pale straw color and die in late May or early June.

The spores remain in aestivation, patiently awaiting the first rains of autumn and back again. That's the simple life of this small fern.

2 comments:

  1. Hello, I found this post while searching on the Internet to try to identify the fern I photographed today. I thought it might be Anogramma leptophylla but after reading your blog, find that it is not.

    You are doing a fantastic thing sharing your obviously detailed knowledge of the natural world. Congratulations.

    I have not been able to identify my fern, but I will mark your blog for further reading.

    Regards,
    Gaye Drady

    ReplyDelete
  2. Thank you very much, Gaye.

    Best Regards.

    ReplyDelete