Not to be semantically confused with :
Lily [a similar-looking flower with similar name but which belongs in a differing family]
Yellow Day-lily (Hemerocallis lilioasphodelus) to which it is directly related and which has slightly smaller flowers at 70-80m which are yellow (not dull-orange) and possess a fragrance of which Orange Day-lily is devoid.
Uniquely identifiable characteristics
Distinguishing Feature :
The fruit is a three-valved capsule about an inch long and half an inch across which slits assunder when ripe to release its seeds. It can also reproduce vegetatively by stolons. Most cultivated varieties are sterile which only propagate vegetatively. It is not native to the UK, but instead to Asia in a region stretching from the Caucases through the Himalayas, China Japan and Korea. It is a perennial and will persist where planted. It spreads rapidly whenever thrown out, by ditches, roadsides, into fields and woods. It forms dense clumps which out-compete and exclude other plants and in some places is so common it is mistaken for a native. However, that doesn't seem to occur anywhere near where the Author lives.
It is called a Day-lily because each flower lasts for but one sunny day, but there is usually another flower bud ready to open the next day, and the day after, for up to a week, or sometimes up to three weeks.
Like Thale Cress (Arabidopsis thaliana) it has a relatively short genome, that and its self-fertilising and in-breeding abilities make it of merit for experimental genomic research likehas Thale Cress.
The taxonomy of the Hemerocallis genus is confused. It was recently moved out of the Hemerocallidaceae family (which was made defunct with no members) family and in 2009 placed amidst the Xanthoriaceae Family (which ultimately derives from the Grass Family tree) but more recent molecular studies have tended to resurrect the Hemerocallidaceae Family and place it back in there. However, the picture is still confused.
Because the flower is extant but one day, several studies have focussed their attention on just how this programmed cell death occurs. Because the turnaround in Day-lily is quick, progress is hastened.
Some references say that the plant is poisonous whereas others treat this suggestion with contempt and readily eat the petals. However, it may not be the petals which are poisonous, and it may not be humanoids to which it is most toxic; other animals may be more susceptible. Certainly it is reported that Hemerocallis genera are neurotoxic and the cause of a unique disease in Australia with symptoms such as brain oedema, Wallerian atrophy of the optic nerve, and de-myelination of central myelin sheaths around the nerves. This results in severe pelvic pain and can also result in permanent blindness in severe cases (usually in cattle). Although, in defence, Hemerocallis species are being cultivated for food. As they say, it is the dose which maketh the poison (even water is poisonous in excess). It seems that most of the Hemerocallin toxin is located in the root and rhizomes, and that aerial parts are relatively free of the substance. Thus it may be alright to eat the flower-heads (in moderation), but beware anything else!
Hemerocallin (a dimer of a naphthalene derivative) is the toxic principle along with other substances. Hemerocallin is a neurotoxic bi-naphthalene tetrol and is identical to the substance Stypandrol which is found in Stypandra imbricata, a lily native to Australia.
Day-lilies also contain a novel naphthalene glycoside, Stelladerol, which has potent anti-oxidant properties. The two glycosidic units are shown in red. It will be seen that the
naphthalene derivative (shown in black) is not quite the same as that in Hemerocallin (note the extra -OH descending from the napthalene group). Other similar glycosides have been isolated in Day-lilies.
Other substances have been isolated from Orange Day-lily including
Adenosine, eight flavones including Kaempferol and three polyphenols based upon
CaffeoylQuinic Acid aka
Chlorogenic Acid. It is reported that methods of reducing the amounts of the very poisonoius alkaloid Colchicine, which is present in Day-lilies (at least in the cultivar 'Panlonghua'), is on-going.
The poisonous spiro-stanol steroidal saponins
Hemeroside A and
Hemeroside B are both found in the aerial parts of the plant, Hemeroside A containing three glycosides, Hemeroside B containing four.
Hemeroside A (aka Hemerocallis A) is 24S-hydroxy-neotokorogenin 1-O-α-L-arabinopyranosyl 24-O-β-D-glucopyranoside
Hemeroside B (aka Hemerocallis B) is isorhodeasapogenin 3-O-β-D-glucopyranosyl- (1-->3)-[β-D-xylopyranosyl- (1-->2)]-β-D-glucopyranosyl- (1-->4)-β-D-galactopyranoside