Botany Photo of the Day

Thank you to Douglas Justice for both today's photograph and accompanying written entry. – Daniel.

Euonymus planipes is a deciduous shrub or small tree native to Korea, northern Japan and eastern Siberia. According to the USDA Germplasm Resources Information Network (GRIN) website, one of the common names is “dingle dangle tree.” Sure it is. The name planipes means “flat stalk,” referring to the flattened petioles of this species. Euonymus species are often difficult to differentiate; many have similar looking leaves and a number share the flattened petiole feature, for example. Identification of Euonymus species can be problematic without careful examination of the overwintering buds and particularly, the ripened (i.e., open) fruit. Features of the fruit that are necessary for many identifications include the shape of the capsule and the colour and vestiture of the seeds. The pure white seeds of E. planipes show an incomplete covering by a fleshy orange aril (all Euonymus species have arillate seeds). The aril is rich in fats and is a reward for birds that disperse these seeds. Note that each seed hangs by its funiculus from the placenta of the fruit wall.

Euonymus are generally excellent garden plants (where they aren’t invasive weeds), but it is worth noting that all parts are considered to be poisonous. The Canadian Biodiversity Information Facility reports that two horses were fatally poisoned after ingesting shoots of European spindle (E. europaeus) and that children are attracted to the fruits of that species and have become “quite ill” after ingesting seeds. The toxic compounds present include a digitalis-like cardiotoxin (evomonoside) and several alkaloids. Birds evidently get around any toxicity by quickly passing them. Most American references rate Euonymus spp. as Class 2 (minor toxicity) plants; i.e., “ingestion of these plants may cause minor illnesses such as vomiting or diarrhea. If ingested, call the Poison Control Center or your doctor.”