Commelina communis Day flower

Day flowers are annual plants. They can be seen around rice fields and roadsides. They flower in mid-June

and begin to wither late in autumn. There are 2 -4 buds in each bract that is folded leaf resembling a clam

There are three types of stamens. They are 2 X-stamens (having the letter X shape anther), 1 inverted V-stamen

(having the inverted V shape anther) and 2 O-stamens (having the letter O shape anther). Pollen is produced by

the inverted V-stamen and O-stamen. It is said that the X-stamen and the inverted V-stamen cannot produce

seeds, so they are called staminodes. Only O-stamen can produce effective pollen. Prominent X-stamens attract

insects. Sometimes some insects can be visiting these flowers and help the pollination.

The flowers open in the morning and close in the afternoon. It is said when the flowers close, both pistils and stamens curl

up and self-pollination occurs. But actually self pollination occurs at late bud stage. That means the difficulty of mating

１．Petals (2 blue petals and 1 small white one that is seen under 3)

２．3 X-stamens (staminodes)

３．1 inverted V-stamen (staminode)

４．2 O-stamens (beige color pollen is seen on the anthers)

５．1 pistil

６．bract

A flower has three transparent sepals, too. They stay in the bract.

I noticed that there are 2 types of flower shape. One has a long narrow appearance resembling a kangaroo face

and another one has a round appearance like a koala because of the wide petals as follows.

　I also noticed that each of the flowers ( kangaroo and koala) has peculiar shape of X-stamens.. I named the X-

stamens butterfly-X and mushroom-X respectively (see the lower picture). Kangaroo face flowers have butterfly-

A Day Flower has three X-stamens. The shapes of them are similar like identical triplets. The flowers from the

one plant have similar shape X-stamens., as well. This means the shape of X-stamen is determined genetically.

I showed butterfly X-stamens of 3 flowers each from one plant. The plants were collected at 8 collection spots.

collection spot　 Ehime prefecture
Ehime prefecture
Ehime prefecture
Ehime prefecture
Ehime prefecture
Ibaragi prefecture
Miyagi prefecture
Miyagi prefecture

Kangaroo types have no hairs of the bract veins and koala types have white hairs of the veins

Fujishima et al (1973)* also reported these two types of bracts. They call them ecologic species.

They observed the size of stomata about the species and reported that no hair types had larger stomata than

white hair types. I also checked the size of stomata of kangaroo and koala type. The epidermis of leaves were


2 flowers in one bract	The erect pedicel has one flower. The lateral one has fruit , flower and two buds.**	Both of the pedicels has no hair on them.	Flower: 3 sepals 3 petals

Flower: 4 staminodes 2 stamens 1 pistil	Anthers of X-stamens ( staminodes)	Anther of inverted V- stamen (staminode) top side	Anther of inverted V- stamen (staminode) back side

Anther of O-stamen	Anther of O-stamen	Pistil	Ovary: white hairs on it

Stigma	4 seeds in a fruit	Seedling	Seedling starts from the embryotega on the seed. ***

** Commelina group plants have the buds in the bracts. There are two type pedicels in the bract. One type is the

erect pedicel and another type is lateral pedicel. Usually the erect pedicel has no flower or one flower

(a male flower is seen more often than a bisexual flower). The lateral pedicel has 2-3 buds and the bud flowers

*** Embryotega: The papillate structure on the seed. The structure is one characteristic of Commelinaceae.