Eranthis byunsanensis in flower

For the moment the common yellow winter aconite is in full bloom, but also the rarer Eranthis byunsanensis from South Korea. I grow it in a peat bed with equal parts of peat and gravel (fraction 4 millimeter). Check out the video and read more about it earlier in my blog.

Why so early flowering?

I got following question from a reader:

I have a yellow flowered eranthis that always flowers in January in my garden in Scotland. This year they appeared about 1st January when the soil temperature and light levels were minimal. I am curious about the physiology that initiates the process and also the evolutionary factors that caused the plants to chose mid winter to flower. I would appreciate any information.

Best wishes, Tony. 

Continental adaptation and competition
for pollinators are key factors for early flowering.

Dear Tony!

I would suggest two reasons for early flowering, both results of evolutionary adaptation. The common winter aconite is a continental floristic element with a typical continental response to seasons. Continental plants start to grow as soon as the first spring heat appears; they respond mainly to temperature and are adapted for clear seasonal changes. When the spring starts in a continental climate setbacks are unlikely so they “know” the spring is for sure. When we move winter aconites from central Europe to maritime Scotland we also move this behavior and they start to grow at the first spring heat there are! Also in southern Sweden there I garden they start to grow in early January since our real winter starts in mid-January and ends in March. Fortunately they are very patient and hardy, so they survive every year and flower in March.

The second answer is, it’s advantageously to flower early because you escape competition of other flowering plants and get all pollinators for yourself! The drawback is if you start to flower too early there are now pollinators awake. The solution of that problem is that many extremely early flowering species have evolved self-pollination or apomixis, so they will set seed without help of pollinators. This is very evident in the two Ranuculaceae genera of Eranthis and Hellebores; you can inbreed both genera and get seedlings in behavior and morphology very close to their parents. All Hellebores breeders today use that phenomenon and most hellebores cultivars you buy are strains and not true clones. Of that reason you also can inbreed cultivars of Eranthis, like double forms, or orange forms.

These two reasons, continental adaptation and competition for pollinators, I would say is the key factors for early flowering in your Scottish garden.

Best wishes
Eric

Eranthis albiflora

Nouv. Arch. Mus. Hist. Nat. II, 8: 191, 1885

China, Thibet oriental: Moupin [Baoxing], March 1869, David (P). China, Sichuan, Tianquan Xian, east side of mount Erlangshan 1700-2050 m, 26 April 1986, Naito et al, No 196 (PE).

Synonyms: Shibatheranthis albiflora (Franch.) Nakai

Illustrations: missing

Eranthis albiflora was described by Adrien Franchet in the year of 1885 from material collected in March 1869 by Armand David during his stay in Mouping (now Baoxing) in western Sichuan, China. Striking is the fact that the 1869 collection seems to be the only record of the species for the next 117 years. Next record is a specimen in Beijing (PE) collected by The Tohoku University China Expedition in the year of 1986. By this reason Eranthis albiflora is one the most unknown species in the genus. Present knowledge bases only on the original collection of David from 1869 (P) and the more recent collection by Naito et al from 1986 (PE). The diagnosis in Flora of China (Liangqian and Tamura 2001) is basically a translation of Franchet’s description from 1885 (Franchet 1885) and so are also the diagnosis in FRPS (1979). The 1986 collection made it possible to fill in information about the tuber which is missing in Franchet 1885 and FRPS 1979.

Eranthis albiflora makes a perennial with globose tuber, 10 cm tall with five to six bracts finely lobed and divided to the middle. In March small flowers (about 15 mm in diameter) appear with translucent white elliptic or oblong sepals encircle four or five funnel-formed bifid petals resembling them in Eranthis byunsanensis. The flower has ten stamens with linear filaments and orbicular anther followed later in spring by four to five follicles each with three to four seeds.

Eranthis albiflora, Sichuan, Erlang Shan (photo Eric Wahlsteen)

Either FoC 2001, FRPS 1979 or Franchet 1885 illustrate the species why pictures of the herbarium sheets have been the only source to recognize the species. On (P) a small drawing probably prepared by Franchet illustrates the parts of the flower, here reproduced after image processing.

Eranthis albiflora, Sichuan, Erlang Shan (photo Eric Wahlsteen)

Eranthis albiflora, narrow leaved form, Hailuogou, Sichuan, China (photo Eric Wahlsteen).

Eranthis albiflora, and narrow leaved form, Hailuogou, Sichuan, China (photo Eric Wahlsteen). 

Description. Rhizome tuberous globose circa 8 mm across, blackish brown with white roots. Basal leaves Leaf blade Involucre consists of five to six bracts. Bracts glabrous, tripartite with obovate-cuneate segments, parted to middle, unequally lobed. Each lobe is linear with acute to obtuse apex. Pedicel short. Flower white, 1.2-1.5 cm across, shortly stalked. Sepals white, elliptic or oblong, obtuse at apex.  Petals 4 or 5 obcordate-funnelform, emarginate outside, bifid inside; stalks long, subequaling blade. Filaments circa ten linear. Anthers orbicular. Style Follicles four or five, sessile, narrowly oblong, 8-10 × 2.5-3 mm. Persistent style 3-5 mm. Seed three or four, flat-globose, 1.8-2 mm across, slightly lucid. 

Distribution:  China: western Sichuan recorded from the counties of Baoxing and in Tianquan on the east side of Erlang Shan, 1700-2100 m.

Habitat. Recorded in grass at margin of mixed forests and on alpine meadows.

Phenology. Flowering March, fruiting May. 

Eranthis albiflora collected by David 1869 outside Baoxing, P. 

Eranthis albiflora collected 1986 by The Tohoku University China Expedition (PE)

Eranthis albiflora colleted by Potanin 1893 showing a great variation within species (LE).

Drawing on the herbarium sheet of David illustrates the parts of the flower. 

Distribution of Eranthis albiflora

Eranthis albiflora in flower

Just back from two weeks in Sichuan, China. Found Eranthis albiflora and can publish probably the first pictures ever of this species in flower.

Eranthis albiflora, Sichuan, Erlang Shan

Nomenclature and systematics

The genus Eranthis has its nomenclatural history in Linnaeus’ Species Plantarum from 1753. Linnaeus treats it as Helleborus hyemalis together with Helleborus niger, H. viridis, H. foetidus and H. trifolius (now Coptis trifolia (L.) Salisb.). In 1807 the winter aconites got their own genus when Salisbury published his essay on the genera of Trollius, Eranthis, Helleborus, Coptis and Isopyrum. In his introduction Salisbury describes the doubt which should push the taxonomic science centuries on:

“Our first vernal flower, the Winter Aconite, which I lately saw in great abundance, has given rise to the above reflections. This plant appears to me a distinct genus, nor can I find any affinity whatever in it, to that in which it has hitherto been placed, beyond the common characters of the order; for the same Nectaria occurs in several others.” (Salisbury 1807)

Over two centuries have past and still we treat the common winter aconite as a good species in a distinct genus. Several new species was described in the 1900-century as a result of exploration of East Asia. The new taxa described by Maximowicz, Turczaninow, Franchet and Candolle hade white flowers and other distinct characters as round tubers and stalked flowers. Maybe Nakai was hit by the same thought as Salisbury when he 1937 published a new generic name for the Asiatic species. He included E. keiskei (now E. pinnatifida Maxim.), E. albiflora, E. longistipitata, E. sibirica, E. stellata and E. uncinata (now E. sibirica) in the new genus Shibateranthis. Nakai distinguished these species by the round tubers, stalked flowers and the elongated stigma. Left for Eranthis (senso stricto) was E. hyemalis and E. cilicica. (Nakai 1937)

Nakai’s treatment was never widely accepted but the name was kept by Tamura in 1987 when he changed its status to sectional level. For Tamura Eranthis was Eranthis but dividable to the sections of Shibateranthis and Eranthis. In the former E. sibirica, E. uncinata, E. stellata, E. albiflora, E. lobulata and E. pinnatifida was placed whereas E. hyemalis (with E. cilicica included) and E. longistipitata was placed in section Eranthis. (Tamura 1987) In 1995 Tamura explains this statement in the key to the sections: Eranthis form a new tuber yearly to make a rhizome and the upper margin of the petals is emarginated or bilobate without swellings. Shibateranthis do not form a rhizome by yearly growth but a tuber and the petals are bilobate or biforked and have lobes with swellings.

The latest contribution to the debate was Luferov’s treatment of Shibateranthis at subgenus level in 2004. He suggests E. pinnatifida, and its synonym E. keiskei , E. lobulata, E. stellata, E. longistipitata, E. albiflora, E. sibirica and the synonym E. isurica (= E. cilicica) for subgenus Shibateranthis and E. hyemalis and E. cilicica for subgenus Eranthis. Luferov follows mostly the treatment of Nakai and explains his statement by spherical tubers, stalked flowers, white, pale yellow or pinkish sepals and elongated stigma for subgenus Shibateranthis.

For such a small genus as Eranthis with only nine species it seems to me premature to talk about subgenus or to divide it into several genera. There is not yet any extensive DNA proofing beside the morphological characteristics, so while waiting for future investigations it seems most arguable to keep the sectional level. However, the main two treatments of Nakai and Tamura are both problematic. Tamura do not agree with Nakai when he puts E. longistipitata to section Eranthis because of the shape of petals and the rhizomatous tuber. Tamura also keep E. albiflora in section Shibateranthis despite its emarginated petals which lacks swellings. By this position he acts against his own sectional key in Tamura 1995.

A phylogenetic investigation confirms a sectional dividing of the genus Eranthis as Tamura 1987 suggests. Based on ten morphological characteristics the nine species was analysed and the two sections was confirmed. The phylogenetic web of figure A links all species with four or less differing characteristics; consequently the most related species. The number by each link indicates the numbers of differing characteristics. As the illustration shows only E. longistipitata bridges E. hyemalis and E. cilicica with the rest of the genus. 

When the web reduces by removing all links of four characteristics a clear dividing of the genus appears, the three yellow flowering species of section Eranthis divide from the white flowering of section Shibateranthis (figure B). 

In next step (figure C) all links of three characteristics are removed. The two groups of E. pinnatifida/byunsanensis and E. sibirica/stellata/lobulata appears but also the outlying position of E. albiflora. The latter is linked to six other species and making it the most linked taxon but only by weak links of four and three characteristics. 

Eranthis pinnatifida Maxim.

Bull. Acad. Imp. Sci. Saint-Pétersbourg xxii. (1877) 225.

Synonyms: Shibateranthis pinnatifida, Eranthis keiskei

Illustrations: The Rock Garden, vol 25., p. 231;

Distribution: According to Ohwi Eranthis pinnatifida is distributed on Japanese Honshu from Kanto and westwards.

Maybe the most well known of the white flowering species. Sepals are pure white, thin like tissue paper and slightly transparent, overlapping or nearly so. Numerous bifid petals with golden yellow spots on each tip, thus easily distinguished from Eranthis byunsanensis with funnel shaped petals. Bracts of involucre are or 1-2 pinnatifid and linear to lanceolate. Rhizome (tuber) globose.


Eranthis pinnatifida is a lowland species so it should be advisable to grow it protected from strong cold, it may be best suited for an alpine house. I grow it in pot with regular peat compost inside greenhouse.

8: distribution of Eranthis pinnatifida (Ohwi)

Eranthis sibirica DC.

Syst. Nat. [Candolle] 1: 315. 1817 [1818 publ. 1-15 Nov 1817]

Synonyms. Eranthis uncinata Turcz.; Helleborus nivalis Siev. ex Ledeb.; Helleborus sibiricus Spreng.

Illustrations

Eranthis sibirica has been known for the science since early 1800th century but maybe as a result of its remote and for long inaccessible habitat it never has been really established in cultivation. Its extremely early appearance in spring can be another explanation to why introduced plants have been short-lived. In semi-mild climate it is a granted victim of late spring frost. As a result Eranthis sibirica has been reported to grow well in the northern parts of Scandinavia there the climate is more continental and the spring more reliable.

Limited access to living plants makes determination hard and the sources are not totally trustworthy. In the Flora of USSR Shipschinskii describes the species as yellow-flowering with some yellow hairs on pedicels and follicles, in contrast to Eranthis sibirica which have its parts covered with white hairs. The yellow flower has probably to do with a yellowed herbarium specimen, since Eranthis sibirica has white flowers as Candolle 1817 describes it. Next problem is the very uncertain characteristic of the hairiness. Shipschinskiis statement how parts of Eranthis stellata are “covered with delicate, white glandular hairs” is certainly not obvious. More distinctly is the pale green colour of the broader lobed involucre bracts and how the flower is faced straight up. In Eranthis stellata the bracts are more delicate lobed and tinged copper and dark green and the flower is often lateral.

Description Rhizome tuberous, subglobose. Basal leaves one. Leaf blade 3-5 with tripartite lobes to the middle. Involucre with narrow entire or trifid bracts. Bracts narrow or trifid, pale green. Pedicel short at first, later elongating, glabrous or glandular-pubescent. Flower white, upright. Sepals 5-6, white, elliptic or oval. Petals rather broad, bifid at apex, 1/4 to 1/3 as long as the sepals. Filaments white, linear. Anthers white. Style Follicles on short stalks, obliquely declinate, narrowly lanceolate or oblong-elliptic with a shortish straight or more or less curved beak. Seed

Distribution. Russia: Siberia in Altai, the Angara River area and Sayan Mountains.

Habitat. Forests, clearings and on mossy localities in mountains.

Phenology: Flowering May-June

Number 15 and 17 show petlas and nectaries of Eranthis sibirica. From Flora USSR, vol 7 p 52.

4: distribution of Eranthis sibirica (Flora USSR).