Commelina erecta (Whitemouth Dayflower)

Commelina erecta (Whitemouth Dayflower) on 9-8-19, #504-18.

Whitemouth Dayflower, Widow’s Tears, Slender Dayflower, Scrub Dayflower

Commelina erecta

(Commelina erecta subsp. erecta)

kom-uh-LIN-uh  ee-RECK-tuh

Synonyms of Commelina erecta (1) (Updated on 12-14-22): Commelina erecta var. typica Fernald
Synonyms of Commelina erecta subsp. erecta (48) (Updated on 12-15-22): Commelina aethiopica C.B.Clarke (1881),cCommelina angustifolia Michx. (1803), Commelina angustifolia Hassk. (1864)(nom. illeg.), Commelina assurgens Larrañaga (1923), Commelina bahiensis Link (1820), Commelina caripensis Kunth (1816), Commelina crispa Wooton (1898), Commelina cyanantha Rojas Acosta (1897), Commelina deficiens Hook. (1826), Commelina elegans Kunth (1816), Commelina elegans var. glabriuscula Seub. (1855), Commelina elegans var. hirsuta Standl. (1930), Commelina ensifolia F.Muell. (1873)(sensu auct.), Commelina erecta f. alba Magrath (1971), Commelina erecta f. albina Fernald (1940), Commelina erecta var. angustifolia (Michx.) Fernald (1940), Commelina erecta f. cana Standl. & Steyerm. (1944), Commelina erecta f. candida Standl. & Steyerm. (1944), Commelina erecta f. crispa (Wooton) Fernald (1940), Commelina erecta var. crispa (Wooton) E.J.Palmer & Steyerm. (1935), Commelina erecta var. deamiana Fernald (1940), Commelina erecta var. glochidea (J.Koenig ex C.B.Clarke) Bhargavan (1989), Commelina erecta var. greenei Fassett (1943), Commelina erecta f. hamipila (C.Wright ex Sauvalle) Brashier (1966), Commelina erecta var. hamipila (C.Wright ex Sauvalle) Fernald (1940), Commelina erecta f. intercursa Fernald (1940), Commelina erecta f. roseopurpurea (Herter) Bacig. (1995), Commelina erecta f. villosa (C.B.Clarke) Standl. & Steyerm. (1944), Commelina gerrardii C.B.Clarke (1881), Commelina guaranitica C.B.Clarke ex Chodat & Hassl. (1903), Commelina guineensis Hua (1895), Commelina hamipila C.Wright (1871), Commelina hirsuta Willd. ex Spreng. (1820)(pro syn.), Commelina kurzii var. glochidea J.Koenig ex C.B.Clarke (1892), Commelina loddigesii Steud. (1840)(not validly publ.), Commelina martiana Seub. (1855), Commelina nashii Small (1903), Commelina pohliana Seub. (1855), Commelina roseopurpurea Herter (1940), Commelina saxicola Small (1903), Commelina setosa Wight ex Wall. (1848)(nom. nud.), Commelina sulcata Link (1820), Commelina sulcata Benth. (1849)(nom. illeg.), Commelina swingleana Nash (1895), Commelina undulata G.Lodd. (1830)(nom. nud.), Commelina undulata var. densivestita Domin (1915), Commelina villosa (C.B.Clarke) C.B.Clarke ex Chodat (1901), Commelina virginica var. angustifolia (Michx.) C.B.Clarke (1881), Commelina virginica var. australis C.B.Clarke (1881), Commelina virginica var. massonii C.B.Clarke (1881), Commelina virginica var. villosa C.B.Clarke (1881), Commelina vogelii C.B.Clarke (1881), Eudipetala deficiens (Hook.) Raf. (1837)

Commelina erecta L. is the accepted scientific name for this species of Dayflower. It was named and described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753.

Accepted Infraspecific Names (3) (Updated on 11-16-21): Commelina erecta subsp. erecta (autonym), Commelina erecta subsp. livingstonii (C.B.Clarke) J.K.Morton,Commelina erecta subsp. maritima (J.K.Morton) J.K.Morton. When an intraspecific taxon is named, an autonym (“type specimen”) is automatically generated which is the closest to the species, usually first identified. Based on my observations and research, the species on my farm is the original Commelina erecta.

The genus, Commelina Plum. ex L., was described as such by Carl von Linnaeus in the first edition of Species Plantarum in 1753. Mr. Linnaeus noted that the genus had been previously named and described by Charles Plumier.

As of 12-15-22 when this page was last updated, Plants of the World Online list 200 species in the Commelina genus. It is a member of the plant family Commelinaceae with 39 genera. Those numbers could change as updates are made on POWO.

Distribution map of Commelina erecta from Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; Retrieved January 30, 2020.

The above distribution map of Commelina erecta from Plants of the World Online shows where the species is native in green and introduced in purple. The map on the USDA Plants Database for North America is similar. 

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.


Commelina erecta (Whitemouth Dayflower) on 9-8-19, #504-19.

2019 was a great year for identifying wildflowers on the farm. I took photos of Dayflowers in 2018 but I was just barely getting started identifying the wildflowers here. In 2019, I decided to ID as many as I could but I got fairly busy at a friend’s farm. It wasn’t until the end of August that I took the first photos of Commelina erecta and I didn’t see any C. communis until September 1.

The Commelina erecta were in a very large colony along kind of ditch where the pasture drains into that leads to the pond. At first, I was checking their flowers sterile anthers for reddish-brown dots which is a characteristic of C. communis. There was a strange problem… The spath-like bracts the flowers emerge from on Commelina erecta are supposed to be fused together while the bracts of C. communis are supposed to be open (like a taco). However, all the flowers in this colony were open instead of fused… The flowers had light blue petals (C. communis has darker flowers) and no reddish-brown dots like C. erecta… So why were their bracts open instead of closed?

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-1.

Flowers emerge from spathelike bracts at the top of the stems.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-2.

Flowers have two upper blue petals and a smaller lower white petal. Flowers have three false anthers and three fertile anthers. The petals are a lighter blue than C. communis and they have no reddish-brown spots.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-3.

Here again, the above photo shows an open bract instead of being fused at the lower third like it is supposed to be… The bract is folded so what looks like the lower part is actually the midrib.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-4.

NICE! Flowers open in succession, but many bracts have two flowers that are open at the same time. Flowers supposedly only last for one day.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-5.

I am running out of words to say about the flowers…

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-6.


Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-7.


Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-8.


Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-9.

The ovaries are where the seed is produced.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-10.

Leaves are lanceolate to slightly ovate and have a sheath that surrounds the stems. The sheaths have small white hairs. Leaves grow in an alternate pattern on the stems.

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-11.

Here is a better photo of the leaf sheaths…

Commelina erecta (Whitemouth Dayflower) on 8-29-19, #617-12.


Commelina communis on the left and Commelina erecta on the right on 9-1-19, #620-10.

Finally, on September 1 as I was leaving the area, I looked down on the left side of where I went in and spotted a few plants with darker blue flowers. I took a closer look and low and behold the sterile anthers had reddish-brown spots. I had found Commelina communis! But, something was weird! Their bracts were fused together where they should have been open! I thought maybe I had them backwards even though I was sure I knew what I was looking for. After I took several photos, I went back inside to check. Sure enough, Commelina communis are supposed to have open bracts. That is one of the feature characteristics that separate it from C. erecta, besides having reddish-brown spots.

Commelina communis on the left and Commelina erecta on the right on 9-1-19, #620-11.

The above photo shows the fused bracts on the C. communis on the left and open bracts of the C. erecta on the right. C. communis bracts are supposed to be open and C. erecta bracts are supposed to be fused… Hmmm…

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-1-19, #620-20.

Most information says Commelina erecta is considered an annual but Steyermark’s Flora of Missouri says they are perennial. Perhaps they are perennial in the southern part of Missouri and in the south. They have somewhat thickened, fibrous roots like a perennial would.

Commelina erecta (Whitemouth Dayflower) colony by the back pond on 9-7-19, #625-2.

Photo of the large colony of Commelina erecta by the pond in the back pasture. Commelina erecta, like other species in the genus, have erect to ascending stems. That means they grow upright until they get long enough to sprawl. Stems on the ground root at the nodes.

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-3.

I took a lot of photos of the flowers and bracts because they are the most interesting part of the plant.

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-4.

I opened this bract which shows two ovaries inside.

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-7.

The above is a good photo showing the flower with a short peduncle between the flower and ovary. Strange how Commelina erecta is supposed to have bracts that are fused together at the lower third… How can they be fused together when a flower is coming out? They are probably fused together initially but open as it matures…

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-8.

The flowers are so neat I can’t help taking a lot of photos of them. You never know when some of the photos are going to be blurry.

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-9.

AHHHHH. I looked at hundreds of flowers and bracts and FINALLY found this one with a fused bract! How about that!

Commelina erecta (Whitemouth Dayflower) by the back pond on 9-7-19, #625-10.

As you can see in the above photo, the bract is fused at the lower third and a flower is starting to emerge next to the stem.

Commelina erecta (Whitemouth Dayflower) on 9-7-19, #625-11.

I didn’t take any new flowers of the Commelina species in 2020. I was too busy identifying more wildflowers and doing other things. Maybe I can take more photos in 2021. Many of the links below give better descriptions and photos.

I also have pages for Commelina diffusa (Spreading Dayflower) and Commelina communis (Asiatic Dayflower) if you are interested.

I haven’t noticed any Commelina erecta or C. diffusa since 2019, but C. communis comes up around the yard in a few areas and in the north flower bed. I will keep looking…

I have enjoyed photographing and learning about the many wildflowers growing on the farm and in other areas. I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the blog). I am not an expert, botanist, or horticulturalist. I just like growing, photographing and writing about my experience. I rely on several websites for ID and a horticulturalist I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at I would enjoy hearing from you.


NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is the most reliable and up-to-date plant database and they make updates on a regular basis. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂


2 comments on “Commelina erecta (Whitemouth Dayflower)

  1. Daniel Layton says:

    These pictures are all of Commelina communis. Note the contrasting veins on the spathes and the lack of auricles at the leaf bases.


    • Hello Daniel! Great to hear from you! In 2019, where I took a lot of the photos of both species, you can tell the difference between the two in several ways. Look at photo #620-10… Commelina communis on the left is a darker blue and has distinctive maroon spots on the anthers. That may not always be the case, because Steyermark’s Flora of Missouri mentions a (former) C. communis var. communis without the spots. Like I mentioned, the colony of C. communis were on one side of the area and C. erecta were on the other. The auricles were not something I considered at the time. I was unable to find either species in 2020 where I saw them in 2019 which is weird since the colonies of C. erecta were fairly large. There are several C. communis here and there along the edge of the yard and in a couple of flower beds this year that weren’t there before. I will check a couple of places again for the C. erecta and see if I can check out the auricles mre closely. Take care and thanks for the comment and suggestion.


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