Archive for March, 2020

Sex Change in Trees (Again)

March 30, 2020

A few years ago I wrote a short note about Sex Change in Trees. Today I have spotted another example of environmental sex determination, this time in Acer pensylvanicum (Striped Maple). Apparently, these trees increasingly flower as females as their health deteriorates.

A recent paper looking at underlying mechanisms “demonstrates that physical trauma in striped maple appears to exhibit a threshold effect in which only the most stressful of physiological cues instigate changes in sex expression …. and that damage stress is strongly correlated with switching to femaleness. ”

Nowt so queer as trees.


In the Garden

March 28, 2020

Recent days have been fine and sunny so I have spent a lot of time gardening. More digging and tidying have resulted in several more caterpillars but they have looked too difficult to identify for me to try. A single click beetle larva (wireworm) in one of the vegetable beds does not concern me  – 100 would be different! Anyway, I like click beetles with their spine and notch system that produces the click and bounces them into the air.

There have been many flies about, mostly small, but some larger like this Eudasyphora (likely E. cyanella or E. cyanicolor) (Thanks, Seth):

Eudasyphora sp.

Eudasyphora sp.

The moth trap yielded four moths, one each of Hebrew Character, Early Grey, Clouded Drab and Red Chestnut.

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The annual plague of white-legged snake millipedes has started. I see I wrote about these a year ago.

MIllipedes on outside wall

MIllipedes on outside wall

There was a chiffchaff in the garden a few days ago (reported to Skye Birds) and a raft of eider singing in the bay. The Herring Gulls were at ease awaiting the tide:

Herring Gulls

Herring Gulls

Last gasps?

March 23, 2020

Neil has sent me a couple of records from February including this nice patch of Hymenophyllum tunbrigense (Tunbridge Filmy-fern) from the Drinan area – the first record in NG51 since 1995 and in pretty much the same place as one of the two records made then.

Hymenophyllum tunbrigense NG51

Hymenophyllum tunbrigense (Tunbridge Filmy-fern)      Photo: N. Roberts

Note the teeth on the indusia  – the cover of the sori which contain the sporangia, the spore-bearing structures. This is the best way to distinguish it from the locally common Hymenophyllum wilsonii (Wilson’s Filmy-fern).


March 23, 2020

Having gone into isolation to avoid Covid-19 this blog is currently reduced to what I find in the garden – or our bit of seashore.

Normally by this time of year I am planning summer activities based on analysis of previous records, but this year I have cancelled Skye Botany Group meetings until further notice and Skye Nature Group is in the same boat. As it stands at the moment, I am unlikely even to head for Skye, so Raasay it is. No real hardship there.

I hope to walk on Raasay without judicial reprimand once the season is further underway. I usually see no-one all day so there is very little risk. It could be the year to collect many Raasay Hieracium (Hawkweed) specimens for expert determination. There are plenty of microspecies recorded in the past, but the understanding and taxonomy have changed since many of these records were made.

Meanwhile, I can report the first New Zealand Flatworm from our garden – no surprise as I was shown one from a few hundred metres away in October 2017. I unintentionally dug up this moth larva a couple of days ago.  I think it is Large Yellow Underwing, one of a number of species that feeds at night and hides underground during the day.

Caterpillar 200320

Large Yellow Underwing (probably)


March 7, 2020

If you struggle with sundews, particularly Drosera intermedia (Oblong-leaved Sundew) and Drosera x obovata (Obovate Sundew (D. rotundifolia x anglica)) there is a useful new guide here.

Drosera intermedia has, in my opinion, been over-recorded in the past in our area.

(N.B. Ignoring a very small number of dubious records,  Drosera x belezeana (D. rotundifolia x intermedia) is known only from a small area in the extreme south of England.)