Online publication; available at: http://jats-truffles.org/truffology/

Truffology 3 (1): 1–7 (2020)

Original peer-reviewed article （原著論文 ； 査読有）

Leucangium microspermum: Re-examination of Japanese L. carthusianum
reveals its taxonomic novelty
日 本 産 Leucangium carthusianum の 再 検 討 結 果 に 基 づ く 新 種
L. microspermum の記載
Kohei Yamamoto1*, Hiromi Sasaki2, Muneyuki Ohmae3, Takamichi Orihara4山本 航平 1*, 佐々木廣海 2, 大前 宗之 3, 折原 貴道 4
1Tochigi Prefectural Museum, 2-2 Mutsumi-cho, Utsunomiya-shi, Tochigi 320-0865, Japan
栃木県立博物館，〒 320-0865 栃木県宇都宮市睦町 2-2

2

Mycologist Circle of Japan, Fujisawa-shi, Kanagawa, Japan
菌類懇話会， 神奈川県藤沢市3

Hokken Co. Ltd., 7-3 Ekihigashimachi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0222, Japan
株式会社北研，〒 321-0222 栃木県下都賀郡壬生町駅東町 7-3

4

Kanagawa Prefectural Museum of Natural History, 499 Iryuda, Odawara-shi, Kanagawa 250-0031, Japan
神奈川県立生命の星 ・ 地球博物館， 〒 250-0031 神奈川県小田原市入生田 499* Corresponding author （主著者）
E-mail: kohei081@yahoo.co.jp

Abstract
The genus Leucangium (Morchellaceae, Pezizales) is a truffle-like ascomycete that includes the type species L.
carthusianum from Europe and North America, as well as a variety from China. Two specimens collected from
subalpine conifer forests in Hokkaido in 2004 and 2011 are the only records of the genus in Japan. Since they
were identified as L. carthusianum without detailed examination, in-depth morphological observation andphylogenetic analysis were necessary to confirm their taxonomic placement. In this study, we critically reexamined the Japanese specimens. Morphologically, the length of ascospores of the Japanese L. carthusianum
was found to be much shorter than that indicated by the original descriptions of the type species and its variety.
Phylogenetic analyses based on two nuclear ribosomal DNA regions showed significant genetic divergence
between the Japanese specimens and other specimens of L. carthusianum, including the variety from China.
Accordingly, we described the second species of the genus Leucangium, L. microspermum, more than a century
after the establishment of the genus.

要旨
Leucangium はヨーロッパおよび北米に分布する基準種 L. carthusianum および中国産の一変種からなる、 チャワンタケ目
アミガサタケ科の地下生子嚢菌類である。 国内では北海道の亜高山帯針葉樹林において、 2004 年と 2011 年の二度本属菌が採集され、 L. carthusianum と同定されていたが、 その信頼性について系統学的手法を含む再検証が必要な状況にあった。 そこで今回、 筆者らは日本産標本の詳細な分類学的検討を行った。 その結果、 日本産標本の子嚢胞子長径は L. carthusianum およびその変種の原記載より著しく小さかった。 また、 核リボソーム DNA の 2 領域の塩基配列に基づく系統解析の結果、 日本産と欧米 ・ 中国産標本との間に顕著な遺伝的分化が見られた。 以上の結果より、 日本産標本を Leucangium に属す第二の独立種とみなし、 新種 L. microspermum として記載した。 なお、 従来日本産標本には和名と© The Japanese Association for Truffle Science (JATS), 20201

Truffology - Volume 3, Issue 1, 2020

Yamamoto et al.: Leucangium microspermum, a new species from Japan

してセイヨウイモタケが充てられていたが、 本種は日本固有の新種と判明したため、 和名をコキイロイモタケと改称する。
和名は濃色 （こきいろ ： 黒みを帯びた濃紫色） を帯びた外皮に基づく。 今後、 本属の和名および日本未報告種である
L. carthusianum の和名として、 セイヨウイモタケを用いることを提案する。
Article Info: Submitted: 8 January 2020

Accepted: 23 March 2020

Published: 31 March 2020

Introduction

lineages may be uncovered from specimens traditionally identified as

The genus Leucangium (Morchellaceae, Pezizales) is a truffle-

L. carthusianum, especially those from outside of Europe, including

like ascomycete. This genus is characterized by a black peridium,

Japanese specimens. Thus, we conducted detailed observations anda solid, white gleba that forms gray to dark gray pockets of fertile

phylogenetic analyses of L. carthusianum from Hokkaido, Japan.

tissue, and distinctive, eye-shaped olivaceous ascospores (Trappe
et al., 2009). The type species, L. carthusianum (Tul. & C. Tul.)

Materials and methods

Paol., was originally described as Picoa carthusiana Tul. & C. Tul.

Morphological observations(Tulasne & Tulasne, 1862). Later, Quélet (1883) established the genus

Two dried specimens collected on September 2004 (H. Sasaki

Leucangium and described the type species, L. ophthalmosporum

481 ; TNS-F-79665) from Furano-shi and on September 2011

Quél. Paoletti (1889) accepted Leucangium, and P. carthusiana(K. Yamamoto 110912-1 ; KPM-NC 27881) from Shikaoi-cho were

was transferred to this genus. Several researchers suspected that L.

used. The distance between two sites was ca. 50 km. Microscopic

ophthalmosporum and L. carthusianum were conspecific (Dumée &observation was conducted based on Yamamoto et al. (2019). The

Burlet, 1923; Knapp, 1951), and the former species was eventuallylength : width ratio were presented as Q values. All specimens

regarded as the synonym of the latter (Szemere, 1965; Trappe, 1971).

were freeze- or oven-dried at 60°C overnight and deposited in the

Thereafter, Leucangium has been a monotypic genus.

Kanagawa Prefectural Museum of Natural History (KPM) andLi (1997) examined the ultrastructure of L. carthusianum

National Museum of Nature and Science, Tokyo (TNS) in Japan.

ascospores and septa of hyphae and assumed that Leucangium isclosely related to members of Morchellaceae. Phylogenetic studies

DNA sequencing and phylogenetic analyses

confirmed this view, illustrating that Leucangium was nested within

Two ascomata (TNS-F-79665 and KPM-NC 27881) were used

Morchellaceae (Kovács et al., 2008; Trappe et al., 2010). By contrast,

for sequencing of the internal transcribed spacer (ITS) region and thea recent phylogenetic study showed that Picoa was nested withinlarge subunit (LSU) of nuclear ribosomal DNA. DNA extraction and

Pyronemataceae (Sibissi et al., 2010).

PCR amplification were performed in accordance with Yamamoto

Leucangium carthusianum was originally reported in France

et al. (2019). Newly generated sequences were deposited in the(Tulasne & Tulasne, 1862) and, thereafter, mostly in the mountainous

DNA Data Bank of Japan (DDBJ; http://www.ddbj.nig.ac.jp)

areas of Southern Europe (Knapp, 1951). In addition, Gilkey (1939)

under LC516713 (ITS) and LC516714 (LSU) for TNS-F-79665 ,recorded this species in Oregon, USA, while Liu & Tao (1990)

and LC514671 (ITS) and LC514672 (LSU) for KPM-NC 27881.

recorded it in Shanxi Province, China. Recently, this species was

DNA sequence similarity was examined using National Center foralso collected from Hokkaido, Japan, and was illustrated in a field

Biotechnology Information (NCBI) BLAST search (https://blast.ncbi.

guide (Sasaki et al., 2016). Thus, L. carthusianum is considered to be

nlm.nih.gov/Blast.cgi?PAGE_TYPE=BlastSearch).

broadly distributed across the mid-latitude regions of the Northern
Hemisphere.

For phylogenetic analysis, thirty sequences of ITS and twentyfive sequences of LSU from species in Morchellaceae, including

Trappe et al. (2009), however, suggested that the North American

all available sequences of sequestrate species, i.e., Fischerula

population might be a different species from the European one.

macrospora Mattir., F. subcaulis Trappe, Imaia gigantea (S. Imai)

Indeed, recent phylogenetic analyses of North American and ItalianTrappe & Kovács, Kalapuya brunnea M.J. Trappe, Trappe & Bonito,

samples revealed that L. carthusianum sequences diverged into

L. carthusianum var. carthusianum, L. carthusianum var. purpureum,

several lineages (Chen & Fan, 2018). Moreover, Chinese collections

were retrieved from NCBI (https://www.ncbi.nlm.nih.gov/nucleotide)were morphologically distinguishable from the specimens fromand included in each dataset. Disciotis venosa (Pers.) Boud. andother regions, and were therefore designated as L. carthusianum var.

Verpa conica (O.F. Müll.) Sw. were selected as outgroups. Multiple

purpureum L. Fan & M. Chen (Chen & Fan, 2018). Further crypticalignment and phylogenetic analyses using the maximum likelihood

2© The Japanese Association for Truffle Science (JATS), 2020

Yamamoto et al.: Leucangium microspermum, a new species from Japan

Truffology - Volume 3, Issue 1, 2020

(ML) and maximum parsimony (MP) methods were conducted based

Abies in September (autumn) (Fig. 1A, B). Ascomata were covered

on Yamamoto et al. (2020). The final alignment was deposited inwith almost black to blackish purple, asperate to partially warty

TreeBASE (accession URL: http://purl.org/phylo/treebase/phylows/

peridium (Fig. 1C). The gleba was rather solid, composed of almost-study/TB2:S25487). ML analysis was conducted under the general

white sterile veins and olivaceous pockets of fertile tissue (Fig. 1D).

time-reversible model of nucleotide substitution, with a discrete

Peridial tissue was pseudoparenchymatous (Fig. 1E, F). Glebal

gamma distribution (+G) and invariant sites (+I) for LSU dataset andtissue was composed of interwoven hyaline hyphae and irregularly

with +I for ITS dataset selected by MEGA X (Kumar et al., 2018).

distributed asci (Fig. 1G). Asci were globose (Fig. 1H) and inamyloid.

Results

Ascospores were eye-shaped and brownish at maturity (Fig. 1I).
These morphologies agreed well with descriptions of L. carthusianum

The two specimens temporarily identified as L. carthusianum werefrom Europe (Montecchi & Sarasini, 2000; Tulasne & Tulasne, 1862)

both collected from subalpine forest floors dominated by Picea orand North America (Gilkey, 1939; Luther, 2009). On the other hand,Fig. 1. Leucangium microspermum collected from Hokkaido, Japan (A–E, G, I: KPM-NC 27881; F, H: TNS-F-79665). E, G: Differential interference contrast microscopy;
F, H, I: Bright-field microscopy. A: Habitat. Arrow indicates the position of ascoma. B: Semi-hypogeous ascoma in a field. C: Ascoma. D: Sectioned ascoma.
E: Peridium (upper) and gleba (lower) mounted in lacto-glycerol. F: Surface of peridium composed of textura angularis mounted in water. G: Gleba mounted inlacto-glycerol. H: Ascospores in an ascus mounted in water. I: Matured ascospores mounted in 5% KOH. Bars: C, D = 1 cm; E = 200 μm; F–I = 50 μm.
図 1．北海道産 L. microspermum（A–E, G, I: KPM-NC 27881; F, H: TNS-F-79665）の子実体外部形態、微細構造および発生地．微細構造はラクトグリセロー
ル （E, G）、 水 （F, H） および 5% KOH （I） での封入時を示す． E, G は微分干渉顕微鏡像， F, H, I は明視野顕微鏡像を示す． A ： 発生地． 矢印は子実体の発生位置を示す． B ： 発生状況． C ： 子実体． D ： 子実体断面． E ： 外皮 （上方） およびグレバ （下方）． F ： 外皮を構成する多角菌組織．
G ： グレバ． H ： 子嚢内部の子囊胞子． I ： 成熟した子嚢胞子． スケール ： C, D = 1 cm; E = 200 μm; F–I = 50 μm．
© The Japanese Association for Truffle Science (JATS), 20203

Truffology - Volume 3, Issue 1, 2020

Yamamoto et al.: Leucangium microspermum, a new species from JapanA	

100/78	
 L.	
  carthusianum	
  	
  US	
  	
  GQ119356	

95/100	
 L.	
  carthusianum	
  	
  US	
  	
  GQ119357	

UEM	
  of	
  Pseudotsuga	
  menziesii	
  	
  CA	
  	
  KT272162	
Leucangium	
  sp.	
  	
  US	
  	
  MF124318	
67/78	 Leucangium	
  sp.	
  	
  US	
  	
  MF124317	
-/76	
Leucangium	
  sp.	
  	
  US	
  	
  GQ119359	
72/98	 Leucangium	
  sp.	
  	
  US	
  	
  GQ119360	
Leucangium	
-/95	
 Leucangium	
  sp.	
  	
  US	
  	
  GQ119358	
93/75	 L.	
  carthusianum	
  var.	
  purpureum	
  	
  CH	
  	
  MG712836	
61/80	 L.	
  carthusianum	
  var.	
  purpureum	
  	
  CH	
  	
  MG712835	
L.	
  carthusianum	
  	
  IT	
  	
  GQ379719	
L.	
  microspermum	
  	
  KPM-­‐NC	
  27881	
  	
  	
  JA	
95/98	 L.	
  microspermum	
  	
  TNS-­‐F-­‐79665	
  	
  	
  JA	
Imaia	
  gigantea	
  	
  US	
  	
  EU327193	
98/100	
 I.	
  gigantea	
  	
  US	
  	
  EU327191	
I.	
  gigantea	
  	
  US	
  	
  EU327194	
100/100	
 I.	
  gigantea	
  	
  US	
  	
  EU327192	
I.	
  gigantea	
  	
  US	
  	
  EU327197	
90/75	
I.	
  gigantea	
  	
  JA	
  	
  EU327196	
100/100	
I.	
  gigantea	
  	
  JA	
  	
  EU327195	
100/99	UEM	
  of	
  Abies	  religiosa	
  	
  ME	
  	
  KF041359	
Fischerula	
  macrospora	
  	
  IT	
  	
  JN048882	
Kalapuya	  brunnea	
  	
  US	
  	
  GQ119351	
K.	
  brunnea	
  	
  US	
  	
  GQ119350	
K.	
  brunnea	
  	
  US	
  	
  GQ119349	
K.	
  brunnea	
  	
  US	
  	
  GQ119354	
100/100	
 K.	
  brunnea	
  	
  US	
  	
  NR_121453	
“Leucangium”	
  sp.	  	
  FJ868976	
K.	
  brunnea	
  	
  US	
  	
  GQ119352	
95/76	
K.	
  brunnea	
  	
  US	
  	
  GQ119353	
Discio=s	
  venosa	
  	
  US	
  	
  KM204667	
Verpa	  conica	
  	
  IT	
  	
  JF908754	

B	
L.	
  carthusianum	
  var.	
  purpureum	
  	
  CH	
  	
  MG712837	
L.	
  carthusianum	
  var.	
  purpureum	
  	
  CH	
  	
  MG712838	
Leucangium	
  sp.	
  	
  US	
  	
  GQ119360	
88/59	
Leucangium	
  sp.	
  	
  US	
  	
  GQ119359	
Leucangium	
  sp.	
  	
  US	
  	
  GQ119358	
96/94	 L.	
  carthusianum	
  	
  US	
  	
  GQ119357	
Leucangium	
73/81	 L.	
  carthusianum	
  	
  US	
  	
  GQ119356	
L.	
  carthusianum	
  	
  US	
  	
  LCU42674	
99/99	
L.	
  carthusianum	
  	
  US	
  	
  GQ119355	
L.	
  carthusianum	
  	
  IT	
  	
  GQ379720	
L.	
  microspermum	
  	
  KPM-­‐NC	
  27881	
  	
  	
  JA	
99/100	 L.	
  microspermum	
  	
  TNS-­‐F-­‐79665	
  	
  	
  JA	
89/94	
Fischerula	
  subcaulis	
  US	
  	
  FSU42673	
100/100	
MSM	
  of	
  Fischerula	
  sp.	
  	
  US	
  	
  JX414173	
99/99	 F.	
  macrospora	
  	
  IT	
  	
  JN048876	
Kalapuya	  brunnea	
  	
  US	
  	
  GQ119350	
K.	
  brunnea	
  	
  US	
  	
  GQ119354	
K.	
  brunnea	
  	
  US	
  	
  GQ119349	
100/100	
 “Leucangium”	
  sp.	  	
  FJ868977	
K.	
  brunnea	
  	
  US	
  	
  GQ119351	
K.	
  brunnea	
  	
  US	
  	
  GQ119353	
75/84	
K.	
  brunnea	
  	
  US	
  	
  GQ119352	
76/-	
Imaia	
  gigantea	
  	
  JA	
  	
  EU327203	
100/100	
I.	
  gigantea	
  	
  US	
  	
  EU327201	
100/86	
 I.	
  gigantea	
  	
  US	
  	
  EU327202	
Discio=s	
  venosa	
  	
  GE	
  	
  AJ698472	
Verpa	  conica	
  	
  US	
  	
  AY544666	
0.02 substitutions/site	

0.09 substitutions/site	

Fig. 2. Maximum likelihood (ML) phylogenetic tree of the internal transcribed spacer (ITS) (A) and large subunit (LSU) (B) sequences of L. microspermum andother truﬄe-like species in Morchellaceae. Disciotis venosa and V. conica were used as outgroups. Bootstrap (BS) values (1,000 replicates) > 50% from ML(left) and maximum parsimony (MP) (right) are shown near nodes. Branches supported by both BS of ML ≥ 70% and MP ≥ 70% (black), and ML ≥ 70% orMP ≥ 70% (gray) are depicted as thick lines. Abbreviations: UEM = uncultured ectomycorrhiza; MSM = mitospore mat; CA = Canada; US = USA; CH = China;
IT = Italy; JA = Japan; ME = Mexico; GE = Germany.
図 2． アミガサタケ科に属する L. microspermum とその他の地下生菌の ITS （A） および LSU （B） データセットに基づく最尤法 （ML） 系統樹． 外群には
D. venosa ならびに V. conica を用いた． ノード付近に， 最尤法 （左） ならびに最節約法 （MP） （右） のブートストラップ値 （BS） を “MLBS/MPBS” として表示した． MLBS ≥ 70% かつ MPBS ≥ 70% で支持された分岐を黒の太線で， MLBS と MPBS のいずれかが 70% 以上の数値を示した分岐を灰色の太線で示した． UEM = 外生菌根由来の環境配列， MSM = 分生子マット由来の配列， CA = カナダ， US = アメリカ， CH = 中国， IT = イタリア， JA =日本， ME = メキシコ， GE = ドイツ．

the dimensions of the ascospores in 5% KOH of the TNS-F-79665

analyses, the statistics of the ITS tree were as follows: tree length =specimen were 42.5–56 × 20–24.5 μm (mean, 49.5 × 23 μm; n = 85),439, consistency index (CI) = 0.877, retention index (RI) = 0.974,

Q = 1.9–2.7 (mean, 2.2; n = 85), and that of ascospores of the KPM-

and composite index = 0.86; those of LSU were tree length = 199,

NC 27881 specimen was 46–62 × 20–27.5 μm (mean, 53.5 × 24 μm;

CI = 0.786, RI = 0.929, and composite index = 0.756. Both ITS andn = 112), Q = 1.7–2.9 (mean, 2.2; n = 112). Hence, the ascospores

LSU trees strongly supported the monophyly of each genus of truffle-of Japanese collections were much smaller than those originallylike fungus in Morchellaceae except for Leucangium whose clade

described (60–80 × 25–30 μm) and most other records from Europe

was strongly supported only by LSU tree. Both trees showed that theand North America (Table 1).

KPM-NC 27881 and TNS-F-79665 specimens were monophyletic

ITS (807 bp and 759 bp) and LSU (635 bp and 859 bp) sequences

and were genetically divergent from the other sequences ofwere obtained from the specimen KPM-NC 27881 and TNS-F-79665,

Leucangium (i.e., L. carthusianum–L. carthusianum var. purpureum–

respectively. The sequence homology of them was 99.3% (754/759

North American Leucangium sp. complex) within the Leucangiumbp) for ITS and 99.5% (626/629 bp) for LSU. The BLAST searchclade (Fig. 2).

showed that ITS sequences from Japanese specimens were mostsimilar to sequences of Leucangium spp., but the homology was only

Taxonomy

89–90%.

Our morphological comparison and phylogenetic analyses

Figure 2 shows the ML phylogenies of ITS (Fig. 2A: ln L = −strongly support that the Japanese specimens of Leucangium

2879.328967) and LSU (Fig. 2B: ln L = − 2307.632231). In the MPshould be treated as a distinct species. Accordingly, we propose

4© The Japanese Association for Truffle Science (JATS), 2020

Truffology - Volume 3, Issue 1, 2020

Yamamoto et al.: Leucangium microspermum, a new species from Japan
Table 1. Known localities and ascospore dimensions of Leucangium spp.
表 1． Leucangium 属種の産地および子嚢胞子サイズ．
Taxon
（種名）

Country（国）

Locality（地域）

L. microspermum

Japan

Hokkaido

L. carthusianum

FranceDauphine
Jura
Vosges Mountains
AlsaceVercors
CantalSchwarzwald
Cuneo; Forlì-Cesena;
Parma; Reggio nell'Emilia
LuccaCaraș-Severin
Kanton Luzern
n/aGermany
Italy

Romania
Switzerland
TunisiaUSA

L. aff. carthusianum
L. carthusianum var.
purpureum

Spain
China

Vegetation Ascospore（子嚢胞子）b（植生）a
Length （長さ） Width（幅）
(μm)
(μm)
As, Qc42.5–56 [49.5] 20–24.5 [23]Pj
46–62 [53.5]
20–27.5 [24]
F, A
60–80
25–30
A
60–80
n/a
Aa
60–75
20–35
Pa, Fe
60–80
20–35
Aa
60–80
20–38
Ps
58–86 [68.6](22)25–31 [27.7]
F, Aa
67–81
27–36
A, P, F
60–75
20–35

Q value（長さ / 幅）
1.9–2.7 [2.2]
1.7–2.9 [2.2]
n/a
n/a
n/a
n/a
n/a
2.1–3 [2.5]n/an/aPm, CaF, A
P
Hl, Rs

n/a
n/a
n/a
n/a

Gori (2005)
Hollós (1911)
Irlet (1985)
Slama et al. (2006)

n/a
n/a
n/a
n/a

Gilkey (1939)
Luther (2009)
Trappe et al. (2009)
Beug et al. (2014)(46)50–60
60–80
59–71

(26)30–36
20–38
25–32

Reference（出典）This study (TNS-F-79665)
This study (KPM-NC 27881)
d
Tulasne & Tulasne (1862)
Quélet (1883)
Laurent (1996)
Laurent (1998)
Astier (1998)
Van Vooren (2017)
Eichler (1898)
Montecchi & Sarasini (2000)

OregonWashington
Pacific Northwest
Western part of
the Pacific Northwest
Valladolid; Segovia
Shanxi Provincen/aPmPt, A, P
Pm

27c
74–80
67–82
60–75(–90)
55–100

16.5c
24–32
28–35
20–35
19–42

H, Qi, CPw

27–60
58–65(–70)

20–35
19–22

n/a
n/a

Calonge et al. (1995)
Liu & Tao (1990)

Hebei ProvinceLp

60–67.5(–70)

20–25(–27.5)

2.4–3.4

Chen & Fan (2018)da
A = Abies; Aa = A. alba Mill.; As = A. sachalinensis (F. Schmidt) Mast.; C = Cistus; Ca = Corylus avellana L.; F = Fagus; Fe = Fraxinus excelsior L.; H =Helianthemum ; Hl = H. lippii Dum. Cours.; Lp = Larix principis-rupprechtii Mayr; P = Picea; Pa = P. abies (L.) H. Karst.; Pj = P. jezoensis (Siebold & Zucc.) Carriè
re var. jezoensis ; Pw = Picea wilsonii Mast.; Pt = Pseudotsuga; Pm = Ps. menziesii (Mirb.) Franco; Ps = Pinus sylvestris L.; Qc = Quercus crispula Blume; Qi = Q.
bcilex L.; Rs = Rhanterium suaveolens Desf. Mean value is shown inside brackets. It is highly likely that the length of scale bars of all photographs in Slama et al.
(2006) is wrong; their correct length are considered to be about 1/3 length. Therefore, the length and width herein are estimate values based on Fig. 5 in Slama et al.
d(2006). Original description.

composed of rounded to polyhedral cells 15–27(–67) μm wide, wall

L. microspermum for the Japanese specimens.

thin or sometimes slightly thickened up to 2.5 μm thick. Glebal tissue
Leucangium microspermum Koh. Yamam., Hir. Sasaki, Ohmae

textura intricata composed of hyphae hyaline, septate, 3.2–12 μm& Orihara, sp. nov.

broad, thin-walled. Asci irregularly distributed, hyaline, ellipsoid,[MycoBank ID: MB 833826]

globose or obovoid, with a stipe in youth, 93.5–118.5 × (57–)65.5–82
Fig. 1.

μm (not including stipe), thin-walled, with 5–8 spores, not reacting in

Diagnosis: The species forms much smaller ascospores than other

Melzer’s reagent with pretreatment in 5% KOH. Ascospores elliptic-

infrageneric taxa of Leucangium.

fusoid, usually apiculate at both ends, surface smooth, 42.5–62 ×

Etymology: From the Greek micro = small and spermum = spored,

20–27.5 μm (mean, 52 × 23.5 μm; n = 197), Q = 1.7–2.9 (mean, 2.2;

referring to the characteristic small ascospore of this species.

n = 197) in 5% KOH, hyaline in youth becoming yellow-brown orHolotype: JAPAN, Hokkaido, Shikaoi-cho, the shore of Lakeolive-brown, thin-walled; nonreactive in Melzer’s reagent; containing

Shikaribetsu, alt. 817 m, semi-hypogeous under Picea jezoensis

2–4 large central oil droplets surrounded by tiny ones in youth, single(Siebold & Zucc.) Carrière var. jezoensis standing by a trail, 12 Sep.

large oil droplet present at maturity.

2011, K. Yamamoto 110912-1 (KPM-NC 27881).

Distribution, habitat, and fruiting season: hypogeous or semi-

Description: Ascomata stereothecia, firm, oblate spheroid, 22–29

hypogeous, solitary under subalpine forest dominated by Abies or× 15–21 mm; surface almost black to dark black-purple, nearly

Picea in Hokkaido, Japan. Found in autumn.

smooth to minutely warty, sometimes becoming rimose, with a

Other specimen examined: JAPAN, Hokkaido, Furano-shi, thefragile basal attachment. Gleba solid, olive brown pockets of fertile

University of Tokyo Hokkaido Forest, under Abies sachalinensis (F.

tissue separated by sterile veins in maturity, sometimes tissue nearby

Schmidt) Mast. and Quercus crispula Blume, 13 Sep. 2004, E. Sano,

peridium partially stained purple, sometimes sterile base present.

H. Sasaki 481 (TNS-F-79665).

Odor not distinctive. Peridium dark brown or purple-brown in lacto-

Note: An ascoma and ascospores of the specimen TNS-F-79665 areglycerol, darker toward the outside surface, 300–380 μm thickillustrated in Sasaki et al. (2016) as L. carthusianum.

© The Japanese Association for Truffle Science (JATS), 2020

5

Truffology - Volume 3, Issue 1, 2020

Yamamoto et al.: Leucangium microspermum, a new species from Japan

Discussion

References

Leucangium spp. always form ascomata near pinaceous trees

Agerer R., Rambold G. (2004–2019) DEEMY – An information system(Table 1), especially Abies, Picea and Pseudotsuga, except in twofor characterization and determination of ectomycorrhizae. Available

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which was also moderately supported by the ITS tree (Fig. 2A).

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undescribed species by Trappe et al. (2010). Because the present
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American lineages differ from European lineage at the species orinfra-species level.

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