Friday, 10 November 2017

Didymodon vinealis

Growing on a stone on a wooded slope made Didymodon vinealis a suitable candidate for this one. The lower leaves were darker than the upper and when dry they looked appressed to the stem. Under the microscope the cells over the costa in the upper part of the leaf were quadrate.

Didymodon vinealis

Tuesday, 4 April 2017

Dicranodontium denudatum

Here's a species that is potentially overlooked and at first site you could be forgiven for thinking this is Dicranella heteromalla. It's not mentioned in the book as a similar species but that's exactly what it was called by an expert bryologist until he got it under the microscope. A distinguishing feature is the deciduous shoots but when absent it can hamper a safe ID. Under the microscope the basal cells will help separate D.denudatum from Dicranella heteromalla.

Dicranodontium denudatum

Scleropodium tourettii

This was an interesting one as this sample was identified in the field by a professional bryologist as Cirriphyllum crassinervium so in theory it should have been straight forward to key out. However, after running through the key it became apparent that this wasn't Cirriphyllum crassinervium. The leaf tip was the first clue being obtuse and not abruptly contracting to leave a short apiculus. This avenue led me then to chose between Rhynchostegium and Scleropodium. The key says that Scleropodium has differing sizes in stem and branch leaves whereas Rhynchostegium has them all the same size. I could see varying leaf sizes so opted for Scleropodium. This group only has two species which can be separated by habit when wet and dry plus S.tourettii has much more concave leaves than S.cespitans looking more like Pseudoscleropodium purum. This species can be eliminated by the long pinnate growth unlike the bushy matted like habit of S.tourettii. As a postscript it is worth mentioning that Rhynchostegium murale is a similar looking plant and should be considered when identifying in the field perhaps.

Scleropodium tourettii

Friday, 9 December 2016

Rhynchostegiella pumila

My biggest weakness in bryophytes is pleurocarps currently so thought I'd start to tackle this group. The first one wasn't easy and having three names didn't help matters either, the other two being Eurhynchium pumilum and Oxyrrhynchium pumilum.
Working through the keys down all uncertain avenues brought me to Scorpiurium circinatum, Amblystegium serpens, Conardia compacta and Oxyrrhynchium hians/speciosum. The two Oxyrrhynchium species were eliminated by their cell length. both are 40┬Ám long whereas mine was only half that. Scorpiurium was ruled out straight away with S.circinatum have appress leaves when dry and not only this both plants look completely different. Amblystegium serpens was ruled out by having a longer narrower leaf shape. Conardia compacta looks quite close but this species has a costa that runs almost to the leaf tip and rhizoidal growth from the back of the costa.

Rhynchostegiella pumila

Rhynchostegiella pumila through the microscope

Wednesday, 28 September 2016

Hygrohypnum ochraceum

At first glance you'd be forgiven for thinking you've found a Hypnum but on closer inspection the presence of a costa is revealed and in this case a forked costa that runs a little over 50% of the leaf. Keying out can be misleading as the stumbling block comes when judging the costa length; if 50% or more you are taken down the wrong part of the key. Once you are aware of this Hygrohypnum becomes the obvious choice. Hygrophypnum ochraceum is tricky to separate from H.luridum in the field but under the compound microscope the presence of inflated colourless alar cells confirms Hygrophynum ochraceum.

Hygrophypnum ochraceum

Thursday, 22 September 2016

Orthotrichum

Orthotrichum mosses are best identified when bearing capsules but as an exercise I decided to have a go at this one and see how far it could be narrowed down. Firstly Orthotrichums on trees can be characterised by their recurved leaf margins sometimes the entire length of the leaf. In the photo below you can see that the leaf tips are quite distinctive too beyond the recurved margin and the nerve is protruding which is also visible in the leaf section in the inset. With the specimen below the leaves were wide spreading with the basal quater curving and the remainder straight.
Elimination: O.anomalum, O.cupulatum, O.rupestre were all eliminated because they grow on rock and mine was on a branch. O.pulchellum has the leaves twisted when dry and O.tenellum has the leave flexuose when dry so these were eliminated too. O.diaphanum has a white hair point so not that one. Others were ruled out on leaf shape and Lyellii due to lack of gemmae. We are now left with a choice of three: O.stramineum, O.affine and O.striatum.
Orthotrichum affine found nearby the mystery Orthotrichum

Orthotricum sp.



Tuesday, 5 April 2016

Parmotrema reticulatum

Always seem to struggle with foliose lichen so the best way to get good at them is to keep trying. First clues were with UV and chemical tests. There was a faint UV+ purple, C- and K+ yellow turning red. Visually the upper surface showed many fine cracks showing the white medulla and the underside was mainly black with brown lobe tips. The rhizines present are simple and fading towards the lobe margins but the lobe tips had some sparse simple rhizines. Overall this was enough information to key out this foliose lichen to Parmotrema reticulatum.

Parmotrema reticulatum underside of lobe

Parmotrema reticulatum upper side of lobe