Acacia Obtusifolia flowering in August

[fractglobal]

I used to be quite interested in alkaloids present in Acacia Obtusifolia and related native Australian wattles, but It's been quite a few years since then.

I recently came across a tree in the middle of an isolated bit of bushland in suburban Newcastle/Central coast area, however, that had a small sign in front of it labelled "Acacia Obtusifolia - Trial Plantation."

Quite a bit of a shock given I'd eventually travelled over 4 hours to find this species back when I heard of them 10 years ago, and quite annoying to find out there was an area the size of a city block populated with them less than 100m away from the house I was living in at the time.

I noticed though, that the plant seemed to be at the peak of flowering. It's always been my understanding(and experience) that A. Obtusifolia flowers only in the summer months.

I took a picture of a cutting from the tree and attached.

[ferret]

obtusifolia flowers I have seen were much paler and not so tightly spaced on flower axis.. and tips of those phyllodes look rather acute. but then there is that sign.. weird. edges of young phyllodes have crusty resin?

[∂an]

The flowering time (and leaf shape?) seem more in line with longifolia or maidenii.

Edited August 17, 2014 by ∂an

[Strontium Dawg]

Looks longi to me

[theuserformallyknownasd00d]

I recently came across a tree in the middle of an isolated bit of bushland in suburban Newcastle/Central coast area, however, that had a small sign in front of it labelled "Acacia Obtusifolia - Trial Plantation."

 

LOL really??

[fractglobal]

LOL really??

Yeah, that was pretty much my own reaction upon finding it.

The flowering time (and leaf shape?) seem more in line with longifolia or maidenii.

Indeed, this was something that had occurred to me. However after exploring the area, another signposted tree was discovered, perhaps 100m away, with "Acacia Longifolia - Sydney Golden Wattle" written on it, followed by a bit of information/sketch diagram of leaves and flowers, just like the information plaques they have in botanical gardens/national parks. I got another cutting off this one and compared it with the first, it's pretty easy to see that they are two separate(albeit very similar) species.

The A. Longifolia was also flowering, but the flowers were a bit longer/thinner than the ones on the Obtusifolia cutting. I figured it was possible the size is slightly variable within either species, but when I went through and compared both cuttings to the multitude of other possible Obtusi/Longi's in the area, the flowers were identical to either one or the other cutting. The ratio of Obtusifolia is about 3:1.

The shape of the phyllodes were almost indistinguishable, the telltale 'bumpiness' along the Obtusifolia's veins(?) was still observable, but the coloration of the phyllodes look to be much more a factor of sunlight exposure than species. The labelled Longifolia was in an area where it would get an enormous amount of sunlight, and the leaves were so pale they seemed almost translucent toward the extremities. Similarly, the branches went from the brown/green I've always remembered, to a deep transparent red colour that reminds me of stainglass windows. Interestingly, this transparency/reddish bark was found in other Acacia in the area, yet they were all easily Identifiable as either Longi or Obtusi by comparing the shape of the flowers to the reference samples(cuttings) I took, as well as the aforementioned 'veins.'

obtusifolia flowers I have seen were much paler and not so tightly spaced on flower axis.. and tips of those phyllodes look rather acute. but then there is that sign.. weird. edges of young phyllodes have crusty resin?

I'm slightly colourblind and have the most difficulty with shades of yellow, so I don't feel confident making an assessment on that. I'll go for another walk soon and check for the crusty resin mentioned.

I don't own a phone, nor a camera, so I won't be able to post a picture of the Longifolia cutting until later tonight. I will try to get some pictures of the trees themselves some time tomorrow if I can.

Edit: Please excuse the horrible structure of the post, I have always had trouble writing in a straightfoward/chronological manner.

Edited August 18, 2014 by fractglobal

[fractglobal]

I've been unable to get access to a camera, and the rain over the last few days made the bushland inaccessable. However a quick trip today allowed me to check the younger phyllodes of both trees. I couldn't find anything I'd identify as a "crusty resin" however the younger phyllodes of the Obtusifolia felt quite oily toward the tip, and had a reddish tinge to them that wasn't present in the Longifolia.

Edit: I should note that it was somewhat difficult to find phyllodes young enough to make the above distinctions, hence why I hadn't noticed them on my first few trips.

Edited August 20, 2014 by fractglobal