Contact Us Host an Event Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Monday - June 22, 2015

From: Nederland, TX
Region: Southwest
Topic: Plant Identification
Title: Difference between Oxalis debilis and Oxalis violacea
Answered by: Nan Hampton

QUESTION:

There are two species of pink oxalis reported to grow here in Jefferson County, Oxalis debilis (introduced) and O. violacea (native). How can I positively identify which one I have growing in my yard?

ANSWER:

Oxalis violacea (Violet woodsorrel) is the native species and Oxalis debilis (Pink wood sorrel) is an escaped ornamental plant that is native to tropical America.  Here is a description of O. debilis from PIER (Pacific Islands Ecosystems at Risk and here are descriptions of O. debilis var. corymbosa from Wildlife of Hawaii and from Q-Bank, a European database of invasive plants.  Here is a description of O. violacea from Illinois Wildflowers and an extensive description from New England Plant Conservation Program.

Here are some comparisons of the two species using the PIER description for O. debilis and the New England Plant Conservation Program description for O. violacea.

Leaves:

O. debilis — 1.5-4.5 cm long, 2-6.5 cm wide

O. violacea — 0.6-1.3 cm long

Sepals:

O. debilis — oblong, 3.5-5 (-6) mm long

O. violacea — 4-7 mm long, glabrous, each with an orange gland at the apex

Petioles:

O. debilis — slender, flexuous, ascending, 10-25 cm long, more or less villous

O. violacea — 7-13 cm long and glabrous 

Petals:

O. debilis — pinkish purple, spatulate, 11-20 mm long

O. violacea — purple to white, 1-2 cm long (10-20 mm long) 

So, to summarize the most obvious differences:

  1. The leaves of O. debilis are longer than those of O. violacea
  2. The sepals of O. violacea have an orange gland at the tip; whereas, none is described for O. debiiis.
  3. The petioles of O. debilis are longer than those of O. violacea and they are hairy; wheras, those of O. violacea are smooth.
Nonetheless, these two plants are very similar.  There is definitely overlap in sepal size and petal length, but there is very little overlap in the sizes of the leaves and the length of the petioles of the two species.  You might be able to use the smoothness or hairyness of the petioles along with their length and the presence or absence or orange glands at the tips of the sepals to separate the two species.

 

 

More Plant Identification Questions

Identity of milkweed vine with smooth seedpod
November 23, 2012 - I believe the vine I am curious about may be Matelea reticulata. However, most of the pictures I have seen of that vine show bumps on the exterior of the seed pod, and the pod I have is green and smo...
view the full question and answer

Plant identification
September 30, 2007 - We found this plant or something or other in our yard, in the area we found it usually stays wet and it was behind a old tree that was done. It has three big green leaves with a white stem that kind ...
view the full question and answer

Identification of shrub looking like honeysuckle in Odessa TX
October 02, 2011 - Bought a shrub in Pecos, TX yesterday. It looks like honeysuckle but the brightest flat orange I have ever seen. Flower and greenery looked like honeysuckle but when I looked on the Internet under or...
view the full question and answer

Plant identification
April 06, 2011 - I'm trying to figure out the name of a plant/shrub purchased a couple years ago. It was a shrub (about medium sized) with yellow blooms that smelled like lemon. I don't think it was lemon balm or le...
view the full question and answer

Need to identify orange tube-like plants in Middleboro, MA
October 23, 2009 - Mr. Smarty Plants~ I live near some industrial companies, and lately I have been finding these orange plants, like tubes almost the top being brownish all over my backyard in the mulch. They have a...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.