One or two Hairy Mitreworts (Mitrasacme pilosa)?

Mitrasacme pilosa var. pilosa (Hairy Mitrewort). Peter Murrell Nature Reserve.

Mitreworts refer to a group of plants of the genus Mitella from the Saxifrage family (see wiki article). These are temperate and arctic North America and Asian plants which, as far as I know, do not occur in Tasmania.

However, the practice of assigning the same common names to plants that are totally not related to one another has been going on for a long time.

It is therefore of little surprise that we find in Tasmania a number of plants called mitreworts as well. These are small herbs which hail from the Loganiaceae, the botanical family that houses the infamous Strychnine tree.

M. pilosa var. pilosa (Hairy Mitrewort). Closeup. Peter Murrell Nature Reserve.

This post is about a small herb known as the Hairy Mitrewort (Mitrasacme pilosa), a widespread species which often occurs in sandy heaths.

Whilst rambling around Peter Murrell Nature Reserve I stumbled on a small patch of what I believe is this plant near a ditch full of exotic grasses.

The plant was an attractive, neatly compact and prostrate herb. It had hairy stems with opposite leaves. In particular, the calyces were extremely hairy. The Hairy Mitrewort came to mind.

I had previously seen the Hairy Mitrewort before in a sandy heath on the Tasman Peninsula but after dredging up the photo I found that the two plants looked rather different.

M. pilosa var. stuartii (Stalked Hairy Mitrewort). Tasman Peninsula.

The one I found at Peter Murrell was compact, had very short pedicels (flower stalks) and extremely hairy calyces whereas the one I saw at the Tasman Peninsular was a less compact herb and slightly erect, had a very long flower stalk, and a close to hairless calyx.

Going back to the Student’s Flora of Tasmania, I found a description of the plant in Part 3 of the flora where Curtis writes:

‘The variants of with flowers borne on long pedicels have been distinguished as var. stuartii. Extreme forms, i.e. those with almost sessile flowers (flowers born on a very short stalk) and those with flowers on pedicels c. 3 cm long are very distinctive.’

This being said, it is probably safe for me to conclude that the Tasman Peninsula specimen belongs to var. stuartii and that the Peter Murrell specimen belongs to var. pilosa, which is the only other variety present in Tasmania.

M. pilosa var. stuartii (Stalked Hairy Mitrewort). Closeup. Tasman Peninsula.

Still, the disparity between the two varieties makes it difficult to accept at face value that it is all the same species. The long pedicels versus the short pedicels on the different varieties would make most think the two were different species. Moreover, the difference in hairiness could also strengthen the argument that there might be two different species here.

According to the Student’s Flora though, plants from different localities exhibit a range of variation, making the assignment of a specimen to a variety difficult in some instances.

As with the Finger-orchids I have written about, this is possibly a species complex worthy of a further taxonomic-molecular study.

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About David Tng

I am David Tng, a hedonistic botanizer who pursues plants with a fervour. I chase the opportunity to delve into various aspects of the study of plants. I have spent untold hours staring at mosses and allied plants, taking picture of pollen, culturing orchids in clean cabinets, counting tree rings, monitoring plant flowering times, etc. I am currently engrossed in the study of plant ecology (a grand excuse to see 'anything I can). Sometimes I think of myself as a shadow taxonomist, a sentimental ecologist, and a spiritual environmentalist - but at the very root of it all, a "plant whisperer"!
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