Cleome serrulata

Time is flying by here in Vernal- it seems just yesterday that all the Astragalus species were in flower! These past few weeks have seen the Eriogonum, Chrysothamnus, and Artemisia genera begin bursting into bloom. It has been amazing witnessing all the different bits of color along the highway this summer, transitioning from the white Oenothera, to the orange Sphaeralcea, to the brown and yellow Helianthus, and finally to the yellow Chrysothamnus genera.


Cleome serrulata near Rangely, Colorado


Such a pretty plant!

This past week we finished collection of Cleome serrulata, or purple beeplant. When first scouting this plant, we saw that some pods on the plant were red, and others were green. Both the red and green pods contained immature green seeds. We found virtually no mature seeds that were still attached to the plant, suggesting that perhaps as soon as the seeds are ripe, the pods split open and the seeds drop to the ground. This was worrisome, because it would mean that we would have a very short window of time in which to collect mature seed before they split open and fell to the ground.


Cleome serrulata with reddish-green seed pods

We wondered if it would be feasible to collect the unripened pods, and see if the seeds would continue to mature off of the plant. We decided to take back the a small sample of Cleome seeds and see if they would continue to develop further and eventually darken and harden in the bag. We filled three paper bags with seeds, the first containing closed green seed pods, the second containing closed red seed pods, and the third containing immature green seeds without a seed pod. After several days, we opened the seed pods and examined the seeds in each of the bags.


Cleome serrulata with red seed pods

Surprisingly, the bag containing closed green seed pods was the only bag with seeds that ripened. It seemed as though the seed pods started out red, then as they began to ripen they turned green. In addition, since the seeds collected in the bag that were not enclosed in a pod did not ripen, we assumed that the presence of the pod was necessary for seed development.

Therefore, we concluded that we should only collect Cleome serrulata seeds that were enclosed in a completely green seed pod, and that these seeds should sit for several days in open paper bags (to prevent molding) while they developed.

By collecting green seed pods, we were able to successfully collect Cleome serrulata. The population we found was fairly large, so we did not have any problem meeting our goal of 20,000 seeds. In addition, we also noticed several albino Cleome serrulata plants, which was pretty cool to see.


White Cleome serrulata plants with green seed pods


All in all, this species was a lot of fun to collect and I am looking forward to wrapping up our last few collections of the year. Until next time!

Jinny (Genevieve) Alexander
Vernal, UT BLM

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