Tuesday, March 15, 2011

Giant sensitive plant/Creeping mimosa (Mimosa invisa)


Woody herb with long trailing stems native to Brazil and introduced to other tropical countries. It is considered as a serious invasive plant. In Flora of Ceylon Volume 1 it is mentioned that this species was once found along the road outside Agricultural station in Peradeniya and it was imported as a green manure (Dassanayaka & Fosberg 1980). However today it is one of widely spread weed of waste lands, along roads and secondary shrub lands etc. 

4 comments:

  1. Is'nt it more or less a large version of Mimosa pudica ? I think i saw these shrubs along either side of the road leading to Hambantota spanning the vast flat land. What are the measures taken to eradicate this invasion?
    I'd keep the comment on the composition to myself... :)

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  2. Hi Patali
    No this plant is a separate species with different characteristics. Rather than spreading throughout wide area sometime covering few square meters unlike its small 'sister' species which only take few square feet area, easiest method of distinguishing these two species from each other is to examine its leaves. M. invisa has bipinnate leaves with 15-25 leaflets while M. pudica is digitate-pinnate with 2-8 pinnae (usually 4) and each pinna with 10-20 pairs of leaflets.
    Pinnate - having leaflets on either side of the leaf axis.
    bi-pinnate - Twice pinnate, so that leaflets attached to secondary axes and not directly on the primary leaf axis
    digitate-pinnate - Pinnae are attached to one point.
    Pinna - Single leaflet of compound leaf
    Pinnae - plural of Pinna.
    Now I can justify my composition ;) Rather than explaining these leaflets and leaves arrangement with hundred of words it is much easy to show it in a picture. That is why my odd composition here of leaves and flowers of this plant in above picture. Main purpose is to highlight leaves arrangement. Over to you. I am eagerly waiting to hear your comment on composition which you kept to yourself....:D

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  3. Ohh... I have only answered to part of your question. Yes I too have encountered it in several localities of the country spanning vast area of land. As far as I am aware no effective measure have been taken not just to eradicate this invasive species but several other invasive plants(Up to date there are about 40 invasive species recorded from Sri Lanka )rather than occasional weeding programs in natural Eco systems - like Horton plains - organised by some environmental NGOs. How effective of them is obvious. What is most important is to immediate eradication of a identified small area before it would spread to wider area. Unfortunately it is extreamly difficult if not impossible in the later stage.

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    Replies
    1. Hi Bushana,

      I'm organizing a giant mimosa clearing program in Colombo and suburbs. Pls forward me if you have any list of identified locations in Colombo District. forward to mlashik@gmail.com.

      Ashik

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