Lobelia sessilifolia
Lobelia sessilifolia is distributed to Japan, the Korean peninsula, and China and grows naturally on wet grasslands in mountain areas.
It is one of the most common autumn flowers in a marsh area and grows in relatively eutrophic circumstances.   It does not tolerate dryness, and grows in a place always surrounded by water.
One of many lobelias, this species grows between 40 and 100 cm in height.   It has a large rhizome and only the aerial part dies in winter.   The stem is yellowish-green in color, hairy in texture and grows upright.
The leaf is lanceolate* in shape and has small sarrations.   It has no stem and alternates in a spiral direction.
Lobelia sessilifolia forms a raceme at the tip of the stalk where bluish-purple flowers bloom sequentially in an upward direction.   The flower is approximately three cm in length and labiates**.   The upper lip is bifid and spreads widely right to left while the lower lip is trifid.   Therefore, the flower looks like a bird flapping its wings.   The projection like a bird neck looking over its shoulder is the stamens and/or the pistil.   It is separated from the throat.  Therefore, the pollinator is a bumblebee which has a large body.
Lobelia sessilifolia is protandrous***.   In the male stage, its five stamens are fused at the anthers to be cylindrical.   The pollen is released inside the tube once.  At that time, the pistil is housed within the tube.   The tips of the lower stamens have a bundle of hairs.   When an insect touches it, the tube releases pollen to adhere to the insect.   When the flower enters female stage, the pistil extends to push pollen out and protrudes from the tube.   After that, the tip of the pistil splits into two.   When pollen protrudes on the part between split tips (the stigma), the flower gets pollinated.
Lobelia sessilifolia is well known as both a beautiful plant and a poisonous plant.   It contains the toxic alkaloid, lobeline, throughout the whole plant.   This toxic plant appears as a village headman killer in the mystery novel, Akuma no temari-uta written by Seishi Yokomizo.

* Having the shape like a lance head which is a narrow oval and tapering to a point at each end.
** A corolla is gamopetalous, zygomorphic, and its limb is divided into two unequal and overlapping parts which is called an upper and lower lip respectively.
*** Refer to the characteristics of flower where the shedding of the pollen occurs before the stigma is receptive.
Classification: Campanulaceae Lobelia
Scientific name: Lobelia sessilifolia Lamb.
Japanese name: Sawa-gikyo
English Name: ---
Native locality: ---
Ecological description: Perennial
RDB : ---
Planting place: Marsh Garden
shiratama-hoshikusa01 shiratama-hoshikusa02
shiratama-hoshikusa03 shiratama-hoshikusa04
shiratama-hoshikusa05
The flower in male stage
shiratama-hoshikusa06
The flower in female stage