#oligoneuron rigidum

[cedar-glade]

Oligoneuron rigidum

Stiff goldenrod, in a sand barren community, Red River Gorge, Kentucky

A quick look at this image can tell you how dry this habitat was. The grass in the back ground, with turkey foot like inflorescence, is big blue stem.  The big blue stem their was dry at the tips, incredibly short, with leaves already producing large amounts of anthocyanins being synthesized as a buffer. The sepia-tone landscape was evident of the progression of the late season there.

[cedar-glade]

William holding the stiff goldenrod rosette gall for a shot on a windy day.

Oligoneuron rigidum, or stiff goldenrod, is a bit of an outlier looking like this.

This is my first time seeing this species, a fairly tough and pubescent one, with this gull type. 

Rossette gall or bunch gulls are less common compared to the stem apple gulls and even rarer when it’s not on Solidago canadensis, S. giganteum, or S. altissima. 

The culprit that forms this gull on the usual species of Solidago is Rhopalomyia solidaginis, a small winter and spring active fly. The fly burrows into the meristem producing the leaf at a bud axis. The meristem tissue goes into a bit of shock and chemical signalling attempts to both continue meristemal growth while also layering parynchema ground tissue around the larva to the point that it becomes cut off from the plant. Swelling and the damage to the meristemal tissue during the early stages of plant growth means that plant hormones responsible for organ growth at the junction of interest are forced to produce more and work harder to fix the issue; however, the issue is not fixed in it’s normal sense, instead, a gall like tumor forms from swelling with multiple rosetting leaves.  the inside of the gall goes through a type of cell death that allows the inner most tissue to become calus with intermediate cells being involved with chemical stew production. The term for calving off the inside of a diseased section to prevent interaction with the pathogen or parasite by producing a gall, cyst, or tumor while utilizing calus is compartmentalization. 

The other common gulls found on the less rigid species of Solidago are the spindle ellipse gull caused by a Moth, Gnorimoschema gallaesolidaginis, and the round stem gull caused by the Goldenrod Gull fly,  Eurosta solidaginis.

If anyone would like to validate the species that may have caused this I would be stoked. I am currently under the assumption this is Rhopalomyia solidaginis. 

I

[botanytoo]

Soil N not microbes favours an exotic plant over natives

Soil N not microbes favours an exotic plant over natives

The first author measuring leaf lengths of exotic and native species in pairwise competition in the greenhouse. Photo credit: L. Aldrich-Wolfe. The resilience of plant communities to invasion by exotic species may depend on the extent to which native and exotic plant performance are mediated by abiotic and biotic components of the soil. In a recent study published in AoB PLANTS by Shivega and…

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