Carolina larkspur (Delphinium carolinianum) ~ Rockport City Cemetery
If you think this larkspur seems unusual, you’re quite right. The mass of blooms, the unusually flattened stem, and the sheer size of the plant — nearly sixteen inches of floral exuberance — are clues that the plant is fasciated: a relatively uncommon condition that produces a variety of abnormalities in the plants it affects.
Sometimes, there is fusion or flattening in the plant — usually in its stem — that results in ribbon-like, coiled, or contorted tissue. Banding at the top of plants can cause them to increase in size and weight, while flowers and leaves growing on a fasciated plant’s flattened stems may be smaller than usual, or more more abundant, as with the larkspur I found at Rockport.
Fasciation has been attributed to a number of causes: genetic mutation, the presence of bacteria, fungi, or viruses; the activity of insects; or even weather conditions such as frost. Any physical damage to the growing point, or apical meristem, can lead to quirks in the production of new flowers, leaves, or stems.
Plant meristems usually produce the round or cylindrical stem we’re accustomed to seeing. In fasciated plants, the meristem flattens out and becomes elongated. Instead of producing a round stem, the mutation causes a flattened stem to develop.
A larkspur’s normal, cylindrical stem
The wide, flattened stem of the fasciated larkspur
Here, a fasciated and top-heavy Indian paintbrush (Castilleja indivisa) shows off its own flattened stem and remarkable size while lying on the ground; unbroken, it had been brought low by the weight of its own growth.
This Brazoria County paintbrush would do for a really large canvas
Here, the banding typical of fasciated stems is obvious.
Looking more like a chrysanthemum than an Indian paintbrush, this remarkable collection of individual blooms and colorful bracts had grown to be more than six inches in diameter.
It may be a bit of a commonplace, but it’s impossible to see these botanical anomalies without saying, “Fasciation is fascinating.”
Comments always are welcome.