The bluebonnet, a common name for several species of the genus Lupinus, is a highly recognizable annual wildflower, particularly the Texas bluebonnet (Lupinus texensis), which is the state flower of Texas. These plants produce small seeds that are the means of propagation. Understanding the characteristics of the bluebonnet seed is helpful for anyone looking to cultivate this plant or ensure safety.
Physical Description of the Seed
The bluebonnet seed is small, often compared to gravel due to its size and dense composition. A mature seed is typically irregularly shaped, often displaying an oval or kidney-like form. Approximately 15,000 to 16,000 seeds can be found in a single pound.
The color of a mature, dried seed is usually dark, ranging from dull brown to shades of gray or mottled black. These seeds possess a hard, protective outer shell that allows them to survive harsh environmental conditions. This tough seed coat must be mechanically or chemically weakened, a process known as scarification, before the seed can germinate.
Formation and Harvesting from the Pod
The seeds develop inside a pod, which is the fruit of the bluebonnet plant. Following the spring bloom, the flowers fade, and the plant begins to form these pods, which initially appear as fuzzy, green, bean-like casings. The bluebonnet is a member of the legume family.
As the plant matures, the pod transitions from green to yellowish or tan before drying to a brittle brown or black. The optimal time for harvesting is when the pods have fully lost their green color but have not yet become completely dry. This timing is important because bluebonnet pods are known to explosively dehisce, or burst open, to scatter the seeds once they are fully dry.
To collect the seeds, pick the pods when they are brown and brittle but still attached to the plant. The pod can then be carefully shelled, similar to a pea or peanut, to reveal the hard seeds inside. Allowing the pods to fully dry in a contained space, like a bag or bowl, helps ensure that any naturally released seeds are collected.
Toxicity Considerations
Bluebonnet seeds contain naturally occurring quinolizidine alkaloids. These substances, which include anagyrine, are concentrated in the seeds and are responsible for the plant’s toxicity. The presence of these alkaloids means the seeds, as well as other parts of the plant, are poisonous if ingested.
Ingesting the seeds poses a health risk to both humans and livestock, with severity depending on the amount consumed. Symptoms of poisoning can affect the nervous system, including lethargy, severe gastrointestinal upset, twitching, and loss of muscle control. In grazing animals, consuming bluebonnets containing anagyrine has been linked to developmental issues in unborn offspring.
Bluebonnet seeds should be kept out of reach of children and household pets. While large animals like cattle and horses may avoid the plant, sheep and goats are more likely to consume the plant. The toxic nature of the bluebonnet seed requires careful handling and storage, especially when collecting them for planting.