Bull. Natn. Sci. Mus., Tokyo, Ser. B, 32(2), pp. 47–65, June 22, 2006

Taxonomic Studies on Dictyostelids. 2. Review of the Voucher
Specimens of Dictyostelium brevicaule, D. mucoroides, and D.
sphaerocephalum Prepared by E. W. Olive and Preserved in the Farlow
Herbarium (FH)
Hiromitsu Hagiwara
Department of Botany, National Science Museum, Amakubo 4–1–1, Tsukuba, 305–0005 Japan
E-mail: h-hagiwa@kahaku.go.jp

Abstract A total of 30 voucher specimens used in Olive (1901) were examined. Of these, 3 specimens were labeled as Dictyostelium brevicaule; 15, as D. mucoroides; and 12, as D. sphaerocephalum. The lectotype of D. brevicaule was designated in this study, and this species wasarranged in the synonymy of D. mucoroides. The group of the specimens labeled as D. mucoroides
could not be distinguished from that of the specimens labeled as D. sphaerocephalum not onlywith regard to the spore size but also other characters. Moreover, both the groups comprised 4 ormore taxa each including 2 common taxa. These results confirmed the statement in Olive (1902),“it may prove desirable to unite these two variable species.”
Key words : cellular slime molds, dictyostelids, D. brevicaule, E. W. Olive, taxonomy.

In 1869, Dictyostelium mucoroides Brefeld
was described as the first species of dictyostelid
cellular slime molds, commonly known as dictyostelids. After 32 years, E. W. Olive compiled
the information on 11 species of dictyostelids
into a monograph that included 5 new taxa
(Olive, 1901). The voucher specimens used in
the monograph were preserved in the cryptogamic herbarium, namely, the Farlow Herbarium(FH), at Harvard University (Olive, 1902). Since
then, however, no attention was focused on these
specimens in studies on dictyostelids, although
the monograph was referred to as a historicallyimportant work (Raper, 1984).
In 1979, I borrowed all the specimens preparedby Olive from the FH and examined them in detail. Previously, I had designated the lectotypes ofPolysphondylium pallidum Olive and D. purpureum Olive (Hagiwara, 1989, 1992). As a partof this study on Olive’s specimens, I reviewed atotal of 30 voucher specimens belonging to 3
white species of Dictyostelium, namely, D. brevicaule Olive, D. mucoroides and D. sphaero-

cephalum (Oud.) Sacc. & March.
Dictyostelium brevicaule was described as a
new taxon that differs from the species D. mucoroides and D. sphaerocephalum in its small
sorocarps with rather rigid sorophores that bearsori of a comparatively large size (Olive, 1901).
Further, Olive (1901) distinguished D. mucoroides from D. sphaerocephalum mainly withregard to the spore size, although he stated “itmay prove desirable to unite these two variable
species.” After more than 80 years, D. sphaerocephalum was completely separated from D. mucoroides based on not by the spore size but by
the branching of sorocarps, migration of pseudoplasmodia, and the presence of the sorophorecollar, and subsequently, both the species wereredescribed (Raper, 1984). Additionally, D.
brevicaule was arranged in a synonymy of D.
mucoroides (Raper, 1984). In Raper (1984),
however, the original illustrations of D. mucoroides were misunderstood in two respects,
namely, macrocyst-like structures were regarded
as true macrocysts and the size of sorocarps was

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Hiromitsu Hagiwara

mistakenly counted one order higher.
In Hagiwara (1984), D. mucoroides and D.
sphaerocephalum were reviewed based on their
original descriptions and illustrations, and D. mucoroides was redescribed on the basis of isolates
obtained from its type locality. Further D. sphaerocephalum was arranged in a synonymy of D.
mucoroides. The review suggested that the concept of D. mucoroides in Raper (1984) was radically distinct from D. mucoroides in itself andthat, on the other hand, the concept of D. sphaerocephalum in Raper (1984) fitted D. mucoroides
in itself. In this study, the taxonomic treatmentsof D. mucoroides and D. sphaerocephalum werein accordance with Hagiwara (1984), not Raper(1984).
Materials
The voucher specimens used by Olive (1901)
were preserved in the Farlow Herbarium (FH),
Harvard University, U.S.A. Among these, 30
specimens that belonged to 3 white species ofDictyostelium were examined. Of the 30 specimens, 3 specimens were labeled as D. brevicaule;
15, as D. mucoroides; and 12, as D. sphaerocephalum. Their conditions, dates of preparation,and origins are listed in Table 1.
Results and Discussion
Dictyostelium brevicaule Olive, Proc. Amer.
Acad. Arts Sci., 37: 340, 1901.
Three specimens were examined. Their conditions and sorocarp morphology were as follows.
#20 (Figs. 1A & 1B)
Sorocarps small, tangled (Fig. 1B), unbranchedor irregularly branched; sorophores gradually tapering from thick bases to thick tips; sori white
to yellowish; spores elliptical, usually 1.5–1.8
times longer than broad, mostly 4.7–5.82.9–3.6
m m (n5).
#21 (Figs. 1C–1H)
Sorocarps small, often with minute satellite

sorocarps (Fig. 1D), unbranched or irregularly
branched; sorophores gradually tapering fromthick bases to thick tips (Figs. 1E–1G); soriwhite; spores elliptical, usually 1.5–1.8 times
longer than broad (Fig. 1H), mostly 4.9–5.9
2.9–3.4 m m (n12).
4-21-’97 (Figs. 2A–2D)
Two sorocarps were mounted. A mount solution dried up.
Sorocarps minute, unbranched (Fig. 2C);
sorophores thin, consisting of single tiers ofcells, 0.56–0.74 mm in length, 10.5–12 m m indiam near the base, 4–5 m m in diam near the tip;
sorophore bases clavate (Fig. 2D), spores elliptical, clearly less than 2.0 times longer than broad(Fig. 2B).
The above mentioned 3 specimens were
judged as syntypes of D. brevicaule based on
their dates of preparation and/or origins. One ofthese specimens, i.e., Specimen #21, was designated as a lectotype in this study, because its
sorocarp morphology fitted the original description of D. brevicaule (Olive, 1901). Of all the 3
specimens, it was preserved in the best condition.
Specimen #21 was identified as D. mucoroides
based on the small sorocarps, thick sorophores(Fig. 1E), and thick spores (Fig. 1H). Therefore,
D. brevicaule was arranged in the synonymy of
D. mucoroides.
Branching near the sorophore base and the occurrence of minute satellite sorocarps along withthe main sorocarp were observed in Specimen#21. These characteristics have been described in
the illustrations of D. mucoroides (Oudemans,
1895; Hagiwara, 1984).
The sorocarps of Specimen 4-21-’97 were
smaller than those of the original descriptionof D. brevicaule (Olive, 1901). Their thinsorophores and spore shape suggested that Specimen 4-21-’97 was D. minutum Raper; however,the spore size (Fig. 2B) was clearly larger thanthat of D. minutum. If this specimen and Specimen #20 originated from the same isolate, it isprobable that small sorocarps were prepared forTaxonomic Studies on Dictyostelids. 2
Table 1.
Species nameD. brevicaule

D. mucoroides

Specimen

List of the specimens examined in this study.
Condition

Date of preparation

Originon sheep dung, Cambridge, Massachusetts,
U.S.A., collected by E. W. Oliveon goat dung, Cambridge, Massachusetts,
U.S.A.

Dry#20

on agarJune 4, 1898

#21

on agar–Slide
4-21-’97
Dry#22

in glyc. eosin

Apr. 21, 1897

on agar–#23

on agar–#24

on agar–#25

on agar

Apr. 1, 1899

#26
#27

on dung
on agarJan. 23, 1897
June 2, 1898

#28

on agar–#29

on dungNov. 2, 1897

Slide
1-12-’97

in glyc.

Jan. 12, 1897

in glyc. eosinin glyc. eosin––

Mar. 17, 1897
Dec. 28, 1897
Jan. 18, 1901
Mar. 10, 1901

3-17-’97
12-28-’97
1-18-’01
3-10-’01
11-22-’01–

Nov. 22, 1901

in glyc.

–

on agaron agar

–
–

#35
#36

on agaron agar–
Apr. 28, 1897

#37

on agar–#38

on agarJune 2, 1898

in glyc. eosin

Apr. 5, 1897

(no date)D. sphaerocephalum Dry
#33
#34

Slide
4-5-’97
4-7-’97
6/5/97
12-21-’97
4-18-’99
1-18-’01

49–––
in glyc. eosin*–

Apr. 7, 1897
June 5, 1897
Dec. 21, 1897
Apr. 18, 1899
Jan. 18, 1901

* acid Delafield’s haematoxylin following osmic fumes

on sheep dungon horse dung, Cambridge, Massachusetts,
U.S.A.
on decaying Polyporus, Cambridge,
Massachusetts, U.S.A., collected by G. R.
Lyman
on rabbit dung, Cambridge, Massachusetts,
U.S.A., collected by E. W. Oliveon sheep dung, Cambridge, Massachusetts,
U.S.A., collected by E. W. Oliveon horse dung, collected by E. W. Oliveon dog dung, Cambridge, Massachusetts,
U.S.A., collected by E. W. Oliveon ass dung, Liberia, Africa, collected by
E. W. Oliveon horse dung, Cambridge, Massachusetts,
U.S.A., collected by F. O. Grover
on horse dung, Cambridge, Massachusetts,
U.S.A.
on dog dungon Liberian ass dung
on deer dung, New York, U.S.A.
on muskrat, Stony Brook, Massachesetts,
U.S.A.
on agarics, Cambridge, Massachusetts,
U.S.A., collected by A. F. Blakeslee
on paper, collected by T. Cawb.
on rat dung, Boston, Massachusetts, U.S.A.
on sea turtle dung, Cambridge, Massachusetts, U.S.A.
on deer dung, New York, U.S.A.
on bush cat dung, Liberia, Africa, collectedby E. W. Oliveon mouse dung, Cambridge, Massachusetts,
U.S.A.
on toad dung, Cocoanut Grove, Florida,
U.S.A., collected by R. Thaxter
on mouse dung, Cambridge, Massachusetts,
U.S.A.,
on bush cat dung, Liberia, Africa
on rat dung, Boston, Massachusetts, U.S.A.
on bird dung, Center Ossipee, New Hampshire, U.S.A.
on turtle dung
on deer dung, New York, U.S.A.

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Hiromitsu Hagiwara

Fig. 1. Dictyostelium brevicaule. A, B. Specimen #20. A. Label of the specimen box. B. Growth habit. 9.
C–H. Specimen #21. C. Label of the specimen box. D. Growth habit. 9. E. Sorocarp with a branch near thebase. 45. F. Terminal part of the sorocarp in Fig. E. 280. G. Basal part of the sorocarp in Fig. E. 450.
H. Spores. 1130.

Specimen 4-21-’97.

lows.

Dictyostelium mucoroides Brefeld, Abh. Senckenberg. Naturf. Ges., 7: 85, pls. 1–3, 1869.
Fifteen specimens were examined. Their conditions and sorocarp morphology were as fol-

#22 (Figs. 3A–3E)
Sorocarps large, tangled (Fig. 3B); sorophores
gradually tapering from thick bases to thin tips
(Figs. 3C & 3D), 50 m m near the base, 8–10 m m

Taxonomic Studies on Dictyostelids. 2

51

Fig. 2. Dictyostelium brevicaule. Specimen 4-21-’97. A. Label of the slide specimen. B. Spores. 1130.
C. Sorocarp. 113. D. Basal part of the sorocarp in Fig. C. 450.

near the tip; sori white to yellowish; spores elliptical, nearly 2 times longer than broad (Fig. 3E),
5.6–6.92.9–3.3 m m (n2).
#23 (Figs. 3F–3I)
Sorocarps medial, tangled (Fig. 3G); sorophores
gradually tapering from bases to thin tips,
25–29 m m in diam near the base, 4.5–7.5 m m indiam near the tip; sorophore tips capitate (Fig.
3H); sori yellowish brown; spores elliptical, usually 1.5–1.8 times longer than broad (Fig. 3F),
mostly 5.2–6.73.2–4.1 m m (n20).
#24 (Figs. 4A & 4B)
Sorocarps very large, tangled (Fig. 4B);
sorophores gradually tapering from thick bases tothin tips, 27.5–55 m m in diam near the base,
5–9.5 m m in diam near the tip; sori white to yellowish; spores elliptical, clearly more than 2times longer than broad.
#25 (Figs. 4C–4F)
Sorocarps small (Fig. 4D), unbranched or irregularly branched; sorophores gradually taper-ing from thick bases to thick tips (Fig. 4E), 20–
50 m m in diam near the base; sori yellowish
brown; spores elliptical, usually 1.5–1.7 times
longer than broad (Fig. 4F), mostly 4.4–5.3
2.8–3.3 m m (n12).
#26 (Figs. 4G, 4H & 5G)
Sorocarps small (Fig. 4H); sorophores gradually tapering from thick bases to thick tips, 32.5–
47.5 m m in diam near the base, 15–20 m m indiam near the tip; sori yellow; spores elliptical,
usually 1.7–2.0 times longer than broad (Fig.
5G), mostly 4.9–5.82.7–3.2 m m (n12).
#27 (Figs. 5A, 5B & 5H)
Sorocarps large, tangled (Fig. 5B); sorophores
gradually tapering from bases to thin tips, 12.5–
37.5 m m in diam near the base, 5.5–7.5 m m indiam near the tip; sori white to yellowish; spores
elliptical, usually 1.6–2.1 times longer than broad(Fig. 5H), mostly 4.4–5.82.5–3.0 m m (n10).
#28 (Figs. 5C & 5D)
Sorocarps medial (Fig. 5D); sorophores

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Hiromitsu Hagiwara

Fig. 3. Dictyostelium mucoroides. A–E. Specimen #22. A. Label of the specimen box. B. Growth habit. 9.
C. Sorophore tip. 450. D. Part of a sorophore near the base. 450. E. Spores. 1130. F–I. Specimen #23.
F. Label of the specimen box. G. Growth habit. 9. H. Sorophore tip. 1130. I. Spores. 1130.

Taxonomic Studies on Dictyostelids. 2

53

Fig. 4. Dictyostelium mucoroides. A–B. Specimen #24. A. Label of the specimen box. B. Growth habit. 9.
C–F. Specimen #25. C. Label of the specimen box. D. Growth habit. 9. E. Sorocarp with two branches near
the base. 45. F. Spores. 1130. G, H. Specimen #26. G. Label of the specimen box. H. Growth habit. 9.

gradually tapering from bases to thin tips; soriwhite to yellowish; spores elliptical, clearly lessthan 2 times longer than broad (Fig. 5I),
5.0–5.43.0–3.2 m m (n2).
#29 (Figs. 5E, 5F & 5J)

Sorocarps large, tangled (Fig. 5F); sorophores
gradually tapering from bases to thin tips,
27.5 m m in diam near the base, 9 m m in diamnear the tip; sori white to yellowish; spores elliptical, usually 1.6–1.9 times longer than broad(Fig. 5J), mostly 5.9–7.13.4–3.9 m m (n11).

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Hiromitsu Hagiwara

1-12-’97 (Figs. 6A–6C)
A cluster of three sorocarps was mounted. A
mount solution dried up.
Sorocarps small, unbranched or irregularly
branched (Fig. 6C); sorophores gradually tapering from thick bases to thick tips (Fig. 6C);
spores elliptical to oblong, clearly less than 2times longer than broad (Fig. 6B).
3-17-’97 (Figs. 6D & 6E)
Two sorocarps were mounted. A mount solution dried up and the sorocarps were molded.
Spores elliptical to oblong, nearly 2 times
longer than broad (Fig. 6E).
12-28-’97 (Figs. 6F & 6G)
Two sorocarps were mounted. A mount solution dried up.
Sorocarps large, unbranched; sorophores
4.7–5.6 mm in length, gradually tapering fromthick bases to thin tips, 45 m m in diam near thebase, 3–5 m m in diam near the tip; spores elliptical, clearly less than 2 times longer than broad(Fig. 6G).
1-18-’01 (Figs. 7A–7D)
One sorocarp was mounted.
Sorocarp small, unbranched, with a basal disk
(Fig. 7C); sorophore 1.7 mm in length, graduallytapering from a thick base to a thick tip (Fig.
7C), 100 m m in diam near the base, 50 m m indiam near the tip; basal disk large (Fig. 7D),
500 m m in diam; spores elliptical, usually 2.1–2.5
times longer than broad (Fig. 7B), mostly 7.5–
8.93.33.8 m m (n20).
3-10-’01 (Figs. 7E–7I)
One immature sorocarp was mounted and mature spores clung onto its sorophore.
Sorocarp large, unbranched; sorophore 3.7 mm
in length, gradually tapering from thick base tothin tip (Figs. 7G–7I), 45 m m in diam near thebase, 8.5 m m in diam near the tip; spores elliptical, usually 2.1–2.4 times longer than broad (Fig.
7F), mostly 6.6–7.62.9–3.4 m m (n11).

11-22-’01 (Figs. 8A–8E)
Three or more sorocarps and several macrocyst-like structures (Fig. 8E) were mounted.
Sorocarps large, unbranched; sorophores 2–7
mm or more in length, gradually tapering frombases to thin tips (Figs. 8C & 8D), 18–30 m m indiam near the base, 5–7.5 m m in diam near thetip; sorophores tip capitate (Fig. 8C); spores elliptical, usually 1.7–2.0 times longer than broad(Fig. 8B), mostly 5.2–6.22.8–3.5 m m (n20).
Macrocyst-like structures 13–31 m m in diam.
(no date) (Figs. 8F–8J)
One sorocarp was mounted.
Sorocarp minute, with a branch near the base(Fig. 8J); sorophore 0.7 mm in length, graduallytapering from a thick base to a thick tip (Fig.
8H), 27.5 m m in diam near the base, 12.5 m m indiam near the tip, having a collar (Fig. 8I); spores
elliptical, usually 1.4–1.7 times longer than broad(Fig. 8G), mostly 3.9–4.62.5–3.0 m m (n20).
A note written on the slide label, namely,“stalk 100 m ” (Fig. 8F), is imcomprehensible.
Specimens #22 and 12-28-’97 were identified
as D. giganteum Singh on the basis of their large
sorocarps, thick sorophore bases, thin sorophore
tips, and thick spores. Specimens #23, #28, #29,
and 11-22-’01 were identified as D. brefeldianum
or its related species on the basis of their medialor large sorocarps, moderately thick sorophorebases, thin sorophore tips, and thick spores. Of
these, two specimens, i.e., Specimens #23 and11-22-’01, probably belonging to D. brefeldianum because their sorophore tips were capitate. Although macrocyst-like structures wereidentified in Specimen 11-22-’01, macrocysts
have not been observed in D. brefeldianum.
Specimens #24, #27, and 3-10-’01 were identified as D. firmibasis Hagiwara or its related
species on the basis of their large sorocarps,
thick sorophore bases, thin sorophore tips, andthin spores. D. firmibasis have not been found in
North America. Specimens #25, #26, and (nodate) were identified as D mucoroides based on
their small sorocarps, thick sorophores, and thickTaxonomic Studies on Dictyostelids. 2

Fig. 5. Dictyostelium mucoroides. A, B. Specimen #27. A. Label of the specimen box. B. Growth habit. 9.
C, D. Specimen #28. C. Label of the specimen box. D. Growth habit. 9. E, F. Specimen #29. E. Label of thespecimen box. F. Growth habit. 9. G. Spores of Specimen #26. 1130. H. Spores of Specimen #27.
1130. I. Spores of Specimen #28. 1130. J. Spores of Specimen #29. 1130.

55

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Hiromitsu Hagiwara

Fig. 6. Dictyostelium mucoroides. A–C. Specimen 1-12-’97. A. Label of the slide specimen. B. Spores. 1130.
C. Three sorocarps growing together. 45. D, E. Specimen 3-17-’97. D. Label of the slide specimen.
E. Spores. 1130. F, G. Specimen 12-28-’97. F. Label of the slide specimen. G. Spores. 1130.

Taxonomic Studies on Dictyostelids. 2

Fig. 7. Dictyostelium mucoroides. A–D. Specimen 1-18-’01. A. Label of the slide specimen. B. Spores. 1130.
C. Sorocarps with a large basal disk. D. Basal part of the sorophore in Fig. C. 280. E–I. Specimen 3-10-’01.
E. Label of the slide specimen. F. Spores. 1130. G. Upper part of a sorophore. 45. H. Lower part of asorophore. 45. I. Basal part of the sorophore in Fig. H. 280.

57

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Hiromitsu Hagiwara

Fig. 8. Dictyostelium mucoroides. A–E. Specimen 11-22-’01. A. Label of the slide specimen. B. Spores. 1130.
C. Sorophore tip. 450. D. Sorophore base. 280. E. Macrocyst-like structure. 450. F–J. Specimen(no data). F. Label of the slide specimen. G. Spores. 1130. H. Sorophore. 113. I. Sorophore tip with acollar (arrow). 450. J. Sorophore base with a branch. 280.

Taxonomic Studies on Dictyostelids. 2

spores. Specimen 1-18-’01 was identified as D.
discoideum Raper based on its large basal disk
and spore size. Specimen 3-17-’97 could not be
identified because other than the spore shape, allits morphological characteristics were obscure.
Dictyostelium sphaerocephalum (Oud.) Sacc. &March., Bull. Soc. Roy. Bot. Belg., 24: 74, pl. 3,
1885.
Twelve specimens were examined. Their conditions and sorocarp morphology were as follows.
#33 (Figs. 9A, 9B & 9G)
Sorocarps medial, tangled (Fig. 9B);
sorophores gradually tapering from bases to thintips, 22.5–32.5 m m in diam near the base, 4.5–
7.5 m m in diam near the tip; sori yellow to yellowish brown; spores elliptical, usually 1.8–2.1
times longer than broad (Fig. 9G), mostly 6.3–
8.03.4–4.1 m m (n20).
#34 (Figs. 9C, 9D & 9H)
Sorocarps small, delicate, tangled (Fig. 9D);
sorophores gradually tapering from bases to thintips, consisting of single tiers cells, 11.5–15 m m
in diam near the base, 2.5–5.5 m m in diam near
the tip; sori white; spores elliptical, usually
1.8–2.1 times longer than broad (Fig. 9H), mostly 6.0–7.03.1–3.5 m m (n9).

59#37 (Figs. 10C, 10D, 10F & 10G)
Sorocarps large, tangled (Fig. 10D); sorophores
gradually tapering from thick bases to thin tips
(Fig. 10F), 25–42.5 m m in diam near the base, 5–
10 m m in diam near the tip; sori yellowish brown;
spores elliptical, usually 1.6–1.9 times longer
than broad (Fig. 10G), mostly 5.8–6.83.3–3.8
m m (n20).
#38 (Figs. 11A–11E)
Sorocarps medial, tangled, unbranched or irregularly branched (Fig. 11B); sorophores gradually tapering from bulbous bases to thin tips
(Figs. 11C & 11D), 21–32.5 m m in diam near thebase, 6 m m near the tip; sori white to yellowish;
spores elliptical, nearly 2 times longer than broad(Fig. 11E), 6.63.4 m m (n2).
4-5-’97 (Figs. 11F & 11G)
Several sorocarps were mounted. A mount solution dried up and the sorocarps were molded.
Spores elliptical, less than 2 times longer thanbroad (Fig. 11G).
4-7-’97 (Figs. 11H & 11I)
Two sorocarps were mounted. A mount solution dried up.
Spores elliptical, less than 2 times longer thanbroad (Fig. 11I).

#35 (Figs. 9E, 9F & 9I)
Sorocarps medial, tangled (Fig. 9F); sorophores
gradually tapering from somewhat thick bases tothin tips, 40 m m near the base, 5–10 m m near thetip; sori yellow to yellowish brown; spores elliptical, usually 1.6–2.1 times longer than broad(Fig. 9I), mostly 5.0–5.92.7–3.3 m m (n20).

6/5/’97 (Figs. 12A–12E)
One sorocarp was mounted.
Sorocarp very large, branched (Fig. 12E);
sorophore more than 8 mm in length, graduallytapering from a thick base to a thick tip, 60 m m indiam near the base, 22.5 m m in diam near the tip;
spores elliptical, usually 2.0–2.4 times longer
than broad (Fig. 12B), mostly 6.4–8.13.0–
3.6 m m (n20).

#36 (Figs. 10A, 10B & 10E)
Sorocarps large, tangled (Fig. 10B); sorophores
gradually tapering from bases to thin tips, 16.5–
25 m m in diam near the base, 5 m m in diam near
the tip; sori yellow to yellowish brown; spores elliptical, mostly 1.6–1.9 times longer than broad(Fig. 10E), mostly 5.4–6.73.2–3.8 m m (n12).

12-21-’97 (Figs. 12F & 12G)
Two sorocarps were mounted. A mount solution dried up and the sorocarps were molded.
Spores elliptical, clearly less than 2 times
longer than broad (Fig. 12G).

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Hiromitsu Hagiwara

Fig. 9. Dictyostelium sphaerocephalum. A, B. Specimen #33. A. Label of the specimen box. B. Growth habit.
9. C, D. Specimen #34. C. Label of the specimen box. D. Growth habit. 9. E, F. Specimen #35. E. Labelof the specimen box. F. Growth habit. 9. G. Spores of Specimen #33. 1130. H. Spores of Specimen #34.
1130. I. Spores of Specimen #35. 1130.

Taxonomic Studies on Dictyostelids. 2

61

Fig. 10. Dictyostelium sphaerocephalum. A, B. Specimen #36. A. Label of the specimen box. B. Growth habit.
9. C, D. Specimen #37. C. Label of the specimen box. D. Growth habit. 9. E. Spores of Specimen #36.
1130. F. Sorophore tip of Specimen #37. 450. G. Spores of Specimen #37. 1130.

4-18-’99 (Figs. 12H & 12I)
One immature sorocarp was mounted.
Sorocarp small, delicate (Fig. 12I).

tip; spores elliptical, usually 1.7–2.1 times longer
than broad (Fig. 13B), mostly 6.3–7.43.4–
4.0 m m (n20).

1-18-’01 (Figs. 13A–13F)
Five sorocarps were mounted.
Sorocarps large, unbranched or irregularly
branched; sorophores 4.1–6.1 mm in length,
gradually tapering from thick bases to thin tips
(Figs. 13C & 13D), 32.5–57.5 (75) m m in diamnear the base, 5–6.5 (25) m m in diam near theSpecimens #33, #35, and #36 were identified
as D. brefeldianum or its related species on thebasis of their medial or large sorocarps, moderately thick sorophore bases, thin sorophore tips,
and thick spores. However, Specimen #35
showed the presence of fairly thick sorophorebases. Specimens #37 and 1-18-’01 were62

Hiromitsu Hagiwara

Fig. 11. Dictyostelium sphaerocephalum. A–E. Specimen #38. A. Label of the specimen box. B. Growth habit.
9. C. Sorophore tip. 450. D. Sorophore base. 450. E. Spores. 1130. F, G. Specimen 4-5-’97. F. Labelof the slide specimen. G. Spores. 1130. H, I. Specimen 4-7-’97. H. Label of the slide specimen. I. Spores.
1130.

Taxonomic Studies on Dictyostelids. 2

Fig. 12. Dictyostelium sphaerocephalum. A–E. Specimen 6/5/’97. A. Label of the slide specimen. B. Spores.
1130. C. Terminal part of a sorophore. 45. D. Sorophore tip. 113. E. Basal part of a sorophore with abranch. 113. F, G. Specimen 12-21-’97. F. Label of the slide specimen. G. Spores. 1130. H, I. Specimen
4-18-’99. H. Label of the slide specimen. I. Sorocarp. 45.

63

64

Hiromitsu Hagiwara

Fig. 13. Dictyostelium sphaerocephalum. A–F. Specimen 1-18-’01. A. Label of the slide specimen. B. Spores.
1130. C, D. Sorophore tips. 280. E. Exceptionally thick sorophore tip. 280. F. Exceptionally thicksorophore base. 113.

identified as D. giganteum on the basis of theirlarge sorocarps, thick sorophore bases, thinsorophore tips, and thick spores. If both theSpecimens #35 and 1-18-’01 have originatedfrom the same isolate, it is probable that Specimen #35 belongs to D. giganteum. Specimen #38
was identified as D. aureo-stipes Cavender,
Raper & Norberg based on its large sorocarp
with several branches and a bulbous sorophorebase. Specimen 6/5/’97 was identified as D.
septentrionalis Cavender based on its very large
sorocarp with a thick sorophore and large spores.
The five other specimens could not be identified.
Of the unidentified specimens, Specimen #34
showed the following distinct characteristics: its
small sorocarps were considerably delicate andits sorophores consisted of single tiers of cells.
Therefore, it may belong to D. monochasioides
Hagiwara.

The results of the identification of all the specimens examined in this study are listed in Table
2. The 3 specimens labeled as D. brevicaule wereidentified to belong to a single taxon, D. mucoroides. The group of 15 specimens labeled as
D. mucoroides could not be distinguished fromthe group of 12 specimens labeled as D. sphaerocephalum not only with regard to their spore size
but also in other characters. Moreover, both thegroups comprised 4 or more taxa, i.e., the specimens in the former group were identified to belong to D. brefeldianum or its related species, D.
discoideum, D. firmibasis or its related species,
D. giganteum, and D. mucoroides. On the other
hand, specimens of D. aureo-stipes, D. brefeldianum or its related species, D. giganteum, andD. septentrionalis were identified in the lattergroup. D. giganteum and D. brefeldianum or its
related species were recognized in both thegroups. Therefore, both the groups were not tax-

Taxonomic Studies on Dictyostelids. 2
Table 2.

Summary of the results of identification in this study.

Species name in Olive (1901)
D. brevicaule

D. mucoroides

D. sphaerocephalum

65

Specimen
Dry
#20
#21
Slide
4-21-’97
Dry
#22
#23
#24
#25
#26
#27
#28
#29
Slide
1-12-’97
3-17-’97
12-28-’97
1-18-’01
3-10-’01
11-22-’01(no date)
Dry
#33
#34
#35
#36
#37
#38
Slide
4-5-’97
4-7-’97
6/5/97
12-21-’97
4-18-’99
1-18-’01

onomically classified into two groups. These
results confirmed the statement in Olive (1902),“it may prove desirable to unite these two variable species.”
Acknowledgement
I thank Dr. Donald H. Pfister, the Farlow
Herbarium, Harvard University, for the loan of
Olive’s specimens.
References
Hagiwara, H., 1984. Review of Dictyostelium mucoroides

Identification
D. mucoroides
D. mucoroides
D. mucoroides
D. giganteum
D. brefeldianum or its related species
D. firmibasis or its related species
D. mucoroides
D. mucoroides
D. firmibasis or its related species
D. brefeldianum or its related species
D. brefeldianum or its related species
D. mucoroides
unidentified
D. giganteum
D. discoideum
D. firmibasis or its related species
D. brefeldianum or its related species
D. mucoroides
D. brefeldianum or its related species
unidentified (cf. D. monochasioides)
D. brefeldianum or its related species (cf. D. giganteum)
D. brefeldianum or its related species
D. giganteum
D. aureo-stipes
unidentified
unidentified
D. septentrionalis
unidentified
unidentified
D. giganteum

Brefeld and D. sphaerocephalum (Oud.) Sacc. etMarch. Bull. Natn. Sci. Mus. Tokyo, Ser. B, 10: 27–41.
Hagiwara, H., 1989. The Taxonomic Study of JapaneseDictyostelid Cellular Slime Molds. 131 pp. National
Science Museum, Tokyo.
Hagiwara, H., 1992. Two forms of Dictyostelium purpureum Olive in Japan. Bull. Natn. Sci. Mus., Tokyo,
Ser. B, 18: 7–5.
Olive, E. W., 1901. A preliminary enumeration of theSorophoreae. Proc. Amer. Acad. Arts Sci., 34: 333–344.
Olive, E. W., 1902. Monograph of the Acrasieae. Proc.
Boston Soc. Natur. Hist., 30: 451–513, pls. 5–8.
Oudemans, C. A. J. A., 1895. Anwisten voor de Flora
Mycologica van Nederlands. 9-10: 39–40, pl. IV.
Raper, K. B., 1984. The Dictyostelids. 453 pp. Princeton
Univ. Press, Princeton, New Jersey.