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).

Eranthis byunsanensis B. Y. Sun

Korean J. Pl. Taxon. 23(1): 22 (1993).

Type: Korea, Chonbuk, Puan-gun, wet valley side along te path to Saebong in Mt. Naebyun, 100 m alt., 9 Mar. 1991. Kim, J. J. (Holotype: JNU, isotypes: JNU)

Illustration: Byung Yun Sun et al: A New Species of Eranthis (Ranunculaceae) from Korea: E. byunsanensis. Korean Journal of Plant Taxonomy, Vol 23, No 1, p. 23.

Distribution: Recorded at several localities in South Korea (100-200 m), but may probably also occur in at least southern North Korea.

A fairly new described species related to the Japanese Eranthis pinnatifida. It has large white flowers compound by broad overlapping sepals and funnel formed petals, not bifid as in Eranthis pinnatifida. The bracts of the involucre are linear and entire, not pinnatifid. Rhizome (tuber) globose.

This species was described 1993 but is still considered doubtful, eg The Plant List (2012-12-03) there it is recorded as synonym for Eranthis pinnatifida. I do not agree, if you see both plants, or even pictures of them, the difference is obvious. Additionally extensive DNA proofing is now present.

In the year of 2009 Eranthis pungdoensis B. U. Oh was described as a distinct species from Eranthis byunsanensis. That species is also regarded as a synonym, but this time rightly I think. Eranthis pungdoensis should have funnel formed petals, much broader than E. byunsanensis and distribution restrictred to Pung-do island.

With respect to its low altitude it should be advisable to grow Eranthis byunsanensis protected from strong cold, as with Eranthis pinnatifida. It may be best suited for an alpine house. 

Funnel formed, cylindrical petals of Eranthis byunsanensis.

7: distribution of Eranthis byunsanensis.

Eranthis stellata Maxim.

Prim. Fl. Amur. 22. 1859

Synonyms: Eranthis uncinata var. puberula Regel & Maack; Eranthis vaniotiana H.Lév.; Shibateranthis stellata (Maxim.) Nakai

Illustrations:

2n=16 (Yuan and Yang 2006)

A neat species on emergence with coppery to bronze tinged bracts. Flower is relatively small, even for a winter aconite, petiolate and often lateral. It is compound by short, narrow, never overlapping white sepals and bifid petals with golden tips. Rhizome (tuber) globose. From China: Jilin and Liaoning, Korea (N & S), Russia: Ussuri. 

A badly understood species described as yellow flowering, probably due yellowed herbarium specimens. This error follows the species from Flora of the USSR to the present edition of Flora of China. The treatment in Flora of the USSR testifies the problem with revisions made solely from herbarium specimens. According to Flora of the USSR the only way to key out Eranthis stellata from Eranthis sibirica is by the hairiness of the plants. I would say the lateral flower (vs. erect) and the coppery bracts (vs. pale green) are equally important and much more easy to determine. My own cultivated specimens of Eranthis stellata are from Jilin (China) and have no visible hairs (but accordning to Flora of USSR and Flora of China they should have...) but lateral flowers and coppery bracts. 

 Eranthis stellata with golden circle of petals and narrow, white sepals.

Eranthis stellata with copper tinged 

bracts forming the involucre.

Number 6, distribution of Eranthis stellata. 

Qiong Yuan and Qin-Er Yang 2006. Tribal relationships of Beesia, Eranthis and seven other genera of Ranunculaceae: evidence from cytological characters, Botanical Journal of the Linnean Society, 150, 267–289

Key to Cultivated and Wild Eranthis

Key to Cultivated and Wild Taxa, Draft

1. Flower petiolate, terrestrial storage organ a tuber, globose or subglobose (section Shibateranthis): 2
+ Flower sessile, terrestrial storage organ a rhizome, oblong, creeping: 9

2. Sepals white: 3
+ Sepals yellow: Eranthis longistipitata

3. Sepals overlapping or nearly so, 10-22 mm long, ovate or ovate-oblong: 4
+ Sepals not overlapping or nearly overlapping, 7-10 mm long, elliptic to oblong: 5

4. Petals distally bifid, Y-shaped; bract lobe pinnatifid: Eranthis pinnatifida
+ Petals funnel formed, distally not Y-shaped; bract lobe linear, entire: Eranthis byunsanensis

5. Pedicel pubescent or glandular; follicles 6-9, short petiolate, pubescent or glandular: 6
+ Pedicel glabrous, follicles 4-9, sessile or short petiolate, glabrous: 7

6. (Pedicel), peduncle and follicles with fine white glandular hair or pubescence; bracts coppery on emergence, flower often lateral: Eranthis stellata
+ Pedicel, peduncle and follicles in sutures with short yellow glandular hair; bracts pale green on emergence, flower often erect: Eranthis sibirica

7. Follicles 4-5, sessile; bract lobes linear; petals funnelform with bifid apex: Eranthis albiflora
+ Follicles 4-9, stalked; bract lobes ovate; petals bifurcate: Eranthis lobulata

9. Bracts mid green on emergence, broad dissected, sepals yellow: Eranthis hyemalis
+ Bracts tinged copper on emergence, finely dissected; sepals shiny golden yellow: Eranthis cilicica

This key is mainly based on own observations, but also:
E. pinnatifida versus E. byunsanensis: Byung Yun Sun et al: A New Species of Eranthis (Ranunculaceae) from Korea: E. byunsanensis. Korean Journal of Plant Taxonomy, Vol 23, No 1, p. 21-26.
E. stellata versus E. sibirica: Flora of the USSR, Vol 5 p. 48-50.
E. albiflora versus E. lobulata: Flora of China