Posted by: Rob Viens | March 23, 2012

Mucor on the Mind

March 23rd was a rather lazy day. Darwin wrote:

“The wind yet continues very light & contrary; there is however to my cost a little swell, enough to make me all day long rather uncomfortable: Occupation is the best cure, & I always have, when leaving a port, the pleasant one of arranging the collections.” (Mar 23)

There is no doubt that Darwin was a collector.  I’m sure it was one of those things that set him on the path to being a naturalist and probably helped to make him quite good at it.  So on this particular day, sailing on the Atlantic, Darwin had to be creative about the samples he collected.  He was probably looking over some older plant samples when he came across one covered in mold. What did he do?  What any good naturalist would – describe and sample it!

This particular mold (a type of fungi) was one that belonged to the genus Mucor (which contains many – maybe 1000’s – of individual species). Mucor grows in the soil, others on plants, on decaying vegetable matter, and even on some forms of animal life. (I really have to wonder if this is potentially one of those species we find in our fridge from time to time.)

Mucor species (from Wikipedia commons):

mucor species

On this particular day in history, Darwin left us a detailed description of this fungi in his Zoological Notes. I include it in its entirety here to show his attention to detail in describing all aspects of the natural world.

“Mucor growing on green ginger: colour yellow, length from 1/20 to 1/15 of an inch.— Diameter of stalk .001, of ball at extremity .006.— Stalk transparent, cylindrical for about 1/10 of length, near to ball, it is flattened. angular & rather broarder: Terminal spherule full of grains, .0001 in diameter & sticking together in planes: When placed in water the ball partially burst & sent forth with granules large bubbles of air.— A rush of fluid was visible in the stalk or cylinder.— If merely breathed on, the spherule was expanded itself & three conical semitransparent projections were formed on surface.— (Much in the same manner as is seen in Pollen) These cones in a short time visibly were contracted & drawn within the spherule.” (Zoological Notes, March 23)

He even “bottled” some mucor and gave it a sample number – #223. Though sadly, this sample did not make a successful trip back to England. On examining samples from the first part of the voyage in 1832, John Henslow had quite a surprise when he opened jar #223.   It was distinct enough that he wrote to Darwin about it:

“For goodness sake what is No. 223 it looks like the remains of an electric explosion, a mere mass of soot—something very curious I daresay” (Correspondence from John Henslow, January 21, 1833)

Alas, poor Mucor – not to be remembered in the annals of evolution along side the finches, rheas, and porcupinefish. But I suppose it will outlive us all, so score 1 point for Mucor. (RJV)

PS – For all your Mucor needs – see the Mucor page on Enjoy!


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