Is Menma from Anohana half-Japanese half-Russian?

Question

I saw a comment under a video which says the following:

A: I’m not sure but wasn’t menma half japanese half russian?

[...]

B: yes. the father is japanese and the mother is russian.

[...]

C: well, that's explain why she's the only one with unique hair in the anime

[...]

D: I’ve noticed in anime if you russian you have gray-ish hair. For example Viktor (Yuri on ice), Lev and Elisa (Haikyuu) and Menma

This is somewhat correct as Irene Honma (mother of Menma) is non-Japanese. But is she actually Russian? There is no mention of Irene being Russian in wiki apart from a note that says:

The name Irène means "peace" in Greek.

Question: Is there any information in source material(manga) regarding the actual ethnicity of Irene Honma? If so, is she Russian?

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Related discussion: Is it known whether Kaori Miyazono is half-Japanese?

Answer 1

Yes, Menma is quarter-Russian.

Here is the quote from Wikipedia

本間 芽衣子（ほんま めいこ）/ めんま .. ロシア人[24]の血を引く母イレーヌから受け継いだ銀髪碧眼と白い肌から、儚げな印象を与えるクォーター[25]の少女。

ロシア人＝Russian, クォーター=quarter.

The sources are:

[24] 『オトナアニメ』vol.21、洋泉社〈洋泉社MOOK〉、2011年8月8日、46-77頁。ISBN 978-4-86248-772-8。p50

and

[25] 小説版(novelized version)

『あの日見た花の名前を僕達はまだ知らない。(上)』、2011年7月25日発売1、ISBN 978-4-8401-3957-1

『あの日見た花の名前を僕達はまだ知らない。(下)』、2012年8月10日発売[2]、ISBN 978-4-8401-4689-0