I was admiring the buttercups growing along the creek and decided to run them through the keys to assure I was calling them by the correct name. I do this with plants that may have caused me some identification problems in the past, just to check myself. My reference sources are greater than they were many years ago and I’m now more practiced at plant identification, so this is my way of confirming my earlier assumptions. Buttercups are known for their bright yellow color and five shiny petals, so there’s usually no problem in getting that far with the identification.
This is Hispid Buttercup, Ranunculus hispidus var. hispidus. At least that’s what it’s called by Gleason & Cronquist in their 1991 manual. G & C combined several recognized species into the single species hispidus and then broke that into three varieties. The combination is supported by some and opposed by others, making it possible to have some heated discussions about this plant’s proper identification. Lumped or split doesn’t make any difference to me. I use G & C because it was used in the preparation of the County Flora List and using the same reference makes it easier for me to compare my discoveries with existing county records.
Hispid refers to the presence of short, stiff hairs. There is certainly no shortage of hairs on this plant. It’s interesting that G & C does not make any mention of hairs when it describes this species.
Sometimes the plant descriptions have you diving into tiny reproductive parts of the flower. G & C uses the shape of the fruit as a dividing character between two of the varieties. This is something that used to confuse me, because I didn’t know how to determine fruit characteristics when all I had to look at was a new bloom.
In some flowers, the shape of the mature fruit is already represented by the female flower parts. A little quick dissection can easily expose the parts you need to see. The two awl-shaped bits to the left give a good idea of what the mature fruit will look like.
Sometimes the plants don’t match any of the descriptions. One of the differences between variety hispidus and variety nitidus, the Swamp Buttercup, is the repose of the sepals, those parts just below the petals. The sepals are supposed to project outward in variety hispidus and hang down along the stalk in variety nitidus. In my plants, the sepals project outward in young blooms like that one to the left. As the flowers age, the sepals begin to whither, then drop down and then drop off. A lot of the flowers appeared fresh when viewed from the top, but a look beneath showed a lack of sepals. Fortunately this isn’t the only character available to divide these two varieties.
Variety hispidus displays a fibrous rooting system with no rhizome formation and no rooting at the nodes of sprawling stems. I’ve been watching these plants for years and this plant definitely exhibits variety hispidus characteristics. I get arguments from people because variety hispidus is supposed to grow in well drained uplands and my plants are growing near and in the creek. Swamp Buttercup, variety nitidus, is supposed to grow in wetland situations, so some people automatically assume that these are variety nitidus because they are growing in the water. I explain, sometimes to no avail, that in the upper reaches of a watershed in extremely well drained areas it’s possible for even the creek beds to behave in a manner consistent with well drained uplands. The creek is often dry most of the summer and the banks are certainly like well drained uplands.
You expect a species that has recognizable varieties to demonstrate a range of traits outside the normal parameters. This plant has added an extra petal to the regular compliment of five.
Another plant has gone to the extreme and doubled the number of petals to ten. I’ll bet a competent horticulturalist could take this plant and develop a line of fine bedding plants.
Well, I guess before the public would really embrace this plant it would have to have more blooms and a more compact form. I personally find it quite showy. I just want to be sure I correctly identify it to everyone else.