MYXOMYCETES OF ALDABRA ATOLL by Bruce Ing and R. J. Hnatiuk

ATOLL RESEARCH BULLETIN NO. 249

MYXOMYCETES OF ALDABRA ATOLL by Bruce Ing and R. J. Hnatiuk

Issued by

THE SMITHSONIAN INSTITUTIOh Washington, D. C., U.S.A.

July 1981

Fig 1. Aldabra A t o l l showing t h e p o s i t i o n of t h e c o l l e c t i n g sites.

MYXOMYCETES OF ALDABRA ATOLL by Bruce Ingl and R. J. Hnatiuk2

ABSTRACT

A f i r s t l i s t of myxomycetes from t h e c o r a l a t o l l of Aldabra i n t h e Indian Ocean i s given. 55 s p e c i e s a r e recorded of which t e n a r e new t o t h e A f r i c a n region. Didymium floccosum Martin, Thind & R e h i l l and Physarum dictyosporum Martin a r e r a r e s p e c i e s p r e v i o u s l y known from I n d i a and America r e s p e c t i v e l y . E c o l o g i c a l n o t e s a r e provided, t h e m a j o r i t y of s p e c i e s occur i n l i t t e r under s c r u b , on coconut husks o r r o t t e n wood.

INTRODUCTION

Myxomycetes have been recorded i n f r e q u e n t l y from remote, oceanic i s l a n d s . I n t e n s i v e s e a r c h i n g of such l o c a t i o n s a t optimal times of y e a r has n o t o f t e n been p o s s i b l e . The r e c o r d s p r e s e n t e d h e r e a r e some of t h e most e x t e n s i v e r e p o r t e d from an i s o l a t e d , t r o p i c a l i s l a n d .

Aldabra i s a c o r a l a t o l l i n t h e western Indian Ocean (9'24's l a t . , 460201E long.) l o c a t e d about 640 km e a s t of Tanzania and 420 km north- west of Madagascar. The a t o l l c o n s i s t s of an oblong r i n g of i s l a n d s around a shallow lagoon. Low c a l c a r e o u s dunes occur a t s e v e r a l p l a c e s around t h e c o a s t , b u t i n t h e main t h e l a n d s u r f a c e (155 km2) i s composed of low-lying limestone which i s o f t e n rugged, f i s s u r e d and p i t t e d , b u t may i n some p l a c e s be f l a t o r undulating s h e e t s and p l a t e s . S o i l , a p a r t from t h e c o a s t a l sands, i s t h i n and tends t o accumulate only i n pockets and d e p r e s s i o n s . The age of t h e land s u r f a c e i s estimated t o be about 80,000 y e a r s s i n c e t h e most r e c e n t emergence from t h e s e a

( B r a i t h w a i t e e t a l . , 1973). The c l i m a t e i s s t r o n g l y s e a s o n a l : summers a r e h o t and humid while w i n t e r s a r e c o o l e r and d r i e r . Most of t h e annual p r e c i p i t a t i o n (940 mm, S t o d d a r t & Mole, 1977) f a l l s a s v i o l e n t showers from December t o A p r i l . The cool season r e c e i v e s almost no

1. Chester College, Cheyney Road, Chester

2. The Royal S o c i e t y Aldabra Research S t a t i o n ; p r e s e n t address:

Western A u s t r a l i a n Herbarium, George S t r e e t , South P e r t h , Western A u s t r a l i a .

Manuscript r e c e i v e d December 1978

--

Eds.

e f f e c t i v e r a i n .

Three major v e g e t a t i o n t y p e s dominate t h e a t o l l , a l t h o u g h many s u b d i v i s i o n s a r e p o s s i b l e (Hnatiuk & Merton, 1979). The low, s p e c i e s - r i c h s h r u b l a n d s a r e t h e most widespread and have o n l y a s p a r s e under- s t o r e y . T a l l woodlands of

C a s u a r i n a e q u i s e t i f o l i a

and

Cocos n u c i f e r a

occur p r i m a r i l y i n a r e a s of deep sand along t h e c o a s t . Grasslands and h e r b l a n d s a r e found along t h e c o a s t and i n s p e c i a l h a b i t a t s i n l a n d . L i t t e r accumulation is l e a s t i n most of t h e g r a s s l a n d s , i n t e r m e d i a t e i n shrubland ( b u t o f t e n o n l y i n u n d i s t u r b e d p l a c e s such a s p i t s i n lime- s t o n e where g i a n t t o r t o i s e s cannot r e a c h ) , and g r e a t e s t i n woodlands, e s p e c i a l l y where coconuts accumulate i n abandoned p l a n t a t i o n s .

The most f a v o u r a b l e h a b i t a t s f o r myxomycetes, i n terms of abundance of s p o r a n g i a , a r e t h e o l d , r o t t i n g p i l e s of coconut husks and n u t s . The husks h o l d much w a t e r and d r y o u t o n l y s l o w l y , t h u s p r o v i d i n g i d e a l c o n d i t i o n s f o r extended p e r i o d s . T h i s i s p a r t i c u l a r l y t r u e a t t h e beginning of t h e d r y season when most o t h e r h a b i t a t s have long s i n c e d r i e d o u t . I n t h e g r a s s l a n d , o n l y

F u l i g o s e p t i c a

was found and t h e n o n l y d u r i n g t h e main wet season. I n shrubland s e v e r a l s p e c i e s i n low c o n c e n t r a t i o n were found i n h a b i t a t s t h a t ranged from deep, p r o t e c t e d l e a f l i t t e r , t o ephemeral l i t t e r under s e a s i d e s c r u b , t o r o t t i n g wood.

COLLFCTING SITES

The c o l l e c t i o n s were made by ^R. Hnatiuk between January and J u l y 1974. The s i t e s a r e l i s t e d under s i x t e e n headings and recorded i n t h e l i s t of s p e c i e s a s numbers.

I l e P i c a r d . The h a b i t a t s sampled i n c l u d e groves of

Cocos n u c i f e r a

L . , i n which t h e p i l e s of r o t t i n g husks and o t h e r l i t t e r were p a r t i c u l a r l y p r o d u c t i v e ; r o t t e n wood and l e a f l i t t e r i n p l a n t e d

C a s u a r i n a e q u i s e t i f o l i a

L. woodland; mangrove p o l e s i n woodpile;

l i t t e r i n s c r u b communities composed of v a r i o u s combinations of

Acalypha c l a o x y l o i d e s

Hutch.,

Maytenus s e n e g a l e n s i s

(Lam.) E x e l l ,

M y s t r o x y l o n a e t h i o p i c u m

(Thunb.1 Leosn.,

Ochna c i l i a t a

Lam.,

Pemphis

a c i d u l a

F o r s t . ,

S i d e r o x y l o n i n e r m e

L.,

Tarenna s u p r a - a x i l l a r i s

(Hemsley) Bremek.,

T o u r n e f o r t i a a r g e n t e a

L . f . , and

T r i c a l y s i a s o n d e r i a n a

Hiern; l i t t e r under

C a r i c a papaya

L. and

T e r m i n a l i a

c a t a p p a

L.; on decayed p a r t s of

Agave s i s a l a n a

P e r r i n e . I n a d d i t i o n c o l l e c t i o n s were made i n t u r f of

S p o r o b o l u s v i r g i n i c u s

L. and on moss-covered c o r a l - r o c k . Nine s e t s o f c o l l e c t i o n s were made between January 24 and J u l y 31.

2. Anse Var. C o l l e c t i o n s ware made n e a r t h e beach i n l i t t e r under

A c a l y p h a

and

Maytenus.

(February.)

3 . P o i n t Hodoul. M a t e r i a l s were g a t h e r e d on r o t t e n

Ochna

wood and on

l i t t e r under dense s c r u b of

M y s t r o x y l o n , S i d e r o x y l o n

and

~ r i c a l y s i a

some 40 m from t h e s e a . (February.)

.

Cinq Cases. S e v e r a l h a b i t a t s were sampled between t h e c o a s t and t h e lagoon, i n c l u d i n g s c r u b of L u m n i t z e r a r a c e m o s a W i l l d . , 800 m i n l a n d ; dead wood o f A p o d y t e s d i m i d i a t a E. Mey. e x Bernh.; l i v i n g f o l i a g e of C y p e r u s s p . , and t h e remains of S o l a n u m n i g r u m L., a s w e l l a s s c r u b of M y s t r o x y l o n and S i d e r o x y l o n . (February.)

5. I l e Malabar. C o l l e c t i o n s from ~ r i c a l y s i a l i t t e r i n a p i t i n t h e

limestone. (February.)

6. I s l e t a t E n t r e Deux. Specimens from l i t t e r . ( ~ e b r u a r y . ) 7. Anse Tamarind. L i t t e r under dense c o a s t a l M y s t r o x y l o n scrub.

(February. )

8. Anse Mais. The c o l l e c t i o n s were made from C o c o s l i t t e r i n t h e s t a n d behind t h e beach. ( A p r i l and May.)

9. I l e E s p r i t . A m i x t u r e of dense s c r u b , C o c o s husks and l i t t e r , dead wood and a l g a f i l m s on c o r a l rock f a c e s . ( A p r i l . )

10. I s l e t s i n t h e south-west c o r n e r of t h e lagoon, s o u t h of I l e E s p r i t . Mostly covered w i t h P e m p h i s s c r u b , c o l l e c t i o n s from wood and l e a f l i t t e r . ( A p r i l . )

11. Polymnie. Specimens c o l l e c t e d on r o t t e n wood. ( A p r i l . )

12. I s l e t s i n t h e lagoon s o u t h of Polymnie. Mostly wood, b a r k and l e a f l i t t e r of S i d e r o x y l o n . ( A p r i l . )

13. I s l e t s i n t h e lagoon s o u t h - e a s t of Passe Houareau. Wood and l i t t e r under P e m p h i s and S i d e r o x y l o n scrub. ( A p r i l . )

14. Dune J e a n Louis. Moss-covered c o r a l rock under s c r u b and i n

l i t t e r of M y s t r o x y l o n , about halfway between s e a and lagoon. ( A p r i l . ) 1 5 . Anse Anglais. Husks of C o c o s i n s t a n d behind t h e beach. (May. ) 16. Near P o i n t Grande T e r r e . On dead wood i n s t a n d of C a s u a r i n a .

(June. )

These s i t e s a r e marked on F i g . 1.

LIST OF SPECIES A r c y r i a c i n e r e a ( B u l l . ) P e r s .

On husks and o t h e r C o c o s l i t t e r , and on dead wood. 1 , 8 , 9 , 1 0 , 1 2 . (10 g a t h e r i n g s . )

Cosmopolitan. ( A , I , M ; Mad.) A. d e n u d a t a (L.) W e t t s t .

On C o c o s husks. 1. ( 3 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M ; Mad, Maur; Marsh.)

A . i n c a r n a t a ( ~ e r s . P e r s .

On r o t t e n wood. 9. (1 g a t h e r i n g . ) Cosmopolitan. ( A t I l M - )

C e r a t i o m y x a f r u t i c u l o s a

( ~ u l l .

^{) Macbr.}

On r o t t e n wood. 9,13. (3 g a t h e r i n g s . )

Cosmopolitan

-

v e r y common i n t h e t r o p i c s . ( A , I , M ; Mad; ~ a r s h . ) C l a s t a d e r m a debaryanum de B l y t t

On Cocos husks. 1 , 8 . ( 5 g a t h e r i n g s . )

Cosmopolitan

-

v e r y common i n t h e t r o p i c s . ( 1 , M . I C r a t e r i u m l e u c o c e p h a l u m ( P e r s

.

⁾ D i t m .

On M y s t r o x y l o n l i t t e r . 14. (2 g a t h e r i n g s . ) Cosmopolitan. ( A I I I M . )

C r i b r a r i a l a n g u e s c e n s Rex

On Cocos husks and r o t t e n bark. 8,9. (2 g a t h e r i n g s . ) Probably cosmopolitan b u t much commoner i n t h e t r o p i c s than elsewhere. ( A , I . )

C . m i c r o c a r p a (Schrad.) P e r s .

On C o c o s h u s k s . 1. ( l g a t h e r i n g . )

Probably cosmopolitan, common i n t h e t r o p i c s . ( A , I , M . ) C . v i o l a c e a Rex

On Cocos husks and r o t t e n bark. 8,15. (2 g a t h e r i n g s . ) Cosmopolitan. @ , I , M - 1

Diachea b u l b i l l o s a (Berk. & B r . ) L i s t e r

On l i t t e r under M y s t r o x y l o n , S i d e r o x y l o n , T o u r n e f o r t i a and T r i c a l y s i a . 1 , 3 . (2 g a t h e r i n g s . 1

Recorded from C e n t r a l , North and South America, S r i Lanka and e a s t e r n Asia.

D. l e u c o p o d i a (Bull. Rost

.

On l i t t e r of C a s u a r i n a e q u i s e t i f o l i a , L u m n i t z e r a , M y s t r o x y l o n and T e r m i n a l i a c a t a p p a . 1 , 4 . (3 g a t h e r i n g s . ) Cosmopolitan.

( A r I l M -

D . r a d i a t a G . L i s t e r & Petch

On l i t t e r under Pemphis and T o u r n e f o r t i a . 1. ( 2 g a t h e r i n g s . Recorded from N i g e r i a , I n d i a , S r i Lanka, Thailand, Panama, C h i l e and F l o r i d a .

Diderma e f f u s u m (Schw.) Morgan

On l i t t e r of A c a l y p h a , M a y t e n u s , M y s t r o x y l o n , P e m p h i s , S i d e r o x y l o n , Tarenna s u p r a - a x i l l a r i s and ~ r i c a l y s i a . 1,5,10,12,13. (12

g a t h e r i n g s . )

Cosmopolitan. ( A , I , M . )

D. h e m i s p h a e r i c u m (Bull. ) Hornem.

On l i t t e r , i n c l u d i n g A c a l y p h a . 2,10. (2 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M . )

Didymium a n e l l u s Morgan

On l i t t e r under S i d e r o x y l o n . 13. (1 g a t h e r i n g . )

Recorded from Europe, North America, I n d i a , S r i Lanka and t h e P h i l l i p i n e s .

D. e x i m i urn Peck

On l i t t e r of M y s t r o x y l o n . 7. (1 g a t h e r i n g . )

The d i s t r i b u t i o n of t h i s s p e c i e s i s u n c e r t a i n a s it i s p a r t of t h e group of t a x a r e l a t e d t o D . n i g r i p e s , r e c e n t l y reviewed by

Nannenga-Bremekamp (1972). I t i s widely recorded i n Europe and may b e cosmopolitan.

D . f l o c c o s u m Martin, Thind & R e h i l l

On b a r k l i t t e r i n coconut grove. 1. (1 g a t h e r i n g . )

This d i s t i n c t i v e s p e c i e s was p r e v i o u s l y known only from t h e t y p e l o c a l i t y , i n t h e Mussoorie H i l l s of n o r t h e r n I n d i a (Martin, Thind

& R e h i l l , 1959) b u t h a s now been found i n Venezuela ( F a r r , 1974.)

D . i n t e r m e d i u m Schroet.

On woody l i t t e r and dead T r i c a l y s i a l e a v e s . 1 , 4 , 1 6 . (4 gatherings.) Recorded from B r a z i l , C e n t r a l and North America and Japan, and

considered t o be a r a r e s p e c i e s . D . l e o n i n u m Berk. & B r .

On woody l i t t e r under scrub. 9. (2 g a t h e r i n g s . )

Recorded from I n d i a , S r i Lanka, Singapore, J a v a , t h e P h i l i p p i n e s , Japan and, r e c e n t l y , from Jamaica ( F a r r , 1974.)

D

.

melanospermum (Per s

.

^Macbr

^.

On dead branch of Solanum n i g r u m . 4. (1 g a t h e r i n g . ) Cosmopolitan. (A

,

^I

,

^{M. )}

D . m i n u s ( L i s t e r ) Morgan

On l e a f l i t t e r of Maytenus and T r i c a l y s i a . 1. ( l g a t h e r i n g . ) Cosmopolitan. ( A I I I M . )

D . n i g r i p e s (Link) Fr.

On l e a f l i t t e r under dense mixed s c r u b . 1 , 3 , 9 . (4 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M e )

D . squamulosum (Alb. & Schw. F r .

On l i t t e r of Cocos, Maytenus and S i d e r o x y l o n . 1 , 2 , 6 . (8 g a t h e r i n g s .

Cosmopolitan. (A, I ,M. ) D

.

v e r r u c o s p o r u m We lden

On M y s t r o x y l o n l i t t e r . 4. (1 g a t h e r i n g . )

Recorded from C e n t r a l and South America and Europe, b u t probably widespread.

F u l i g o s e p t i c a ( L . Web.

On r o t t e n C a s u a r i n a wood, on S p o r o b o l u s t u r f and on sedge t u r f i n open coconut grove. 1 , 8 . ( 4 g a t h e r i n g s . ) Cosmopolitan.

( A , I , M ; Mad, Maur; Marsh.)

~ e m i t r i c h i a c a l y c u l a t a (Speg. ) F a r r ( s t i p i t a t a (Mass. ) Macbr

.

⁾

On

cocos

husks. 1 , 8 , 9 . (10 g a t h e r i n g s . )

Cosmopolitan, e s p e c i a l l y common i n t h e t r o p i c s . ( A t I t M ; Maur;

Marsh. )

H . s e r p u l a (Scop. ) Rost.

On

cocos

husks. 1. (1 g a t h e r i n g .

Cosmopolitan, e s p e c i a l l y common i n t h e t r o p i c s . ( A , I , M ; Mad;

Marsh.

Lycogala e p i d e n d r u m (L. ) Fr.

On Agave stump. 1. (1 g a t h e r i n g . ) Cosmopolitan. (A, I , M ; Maur

.

⁾

Meta

t r i

chid v e s p a r i um ( ~ a t s c h ) Nann

.

^-Brem

^.

On Cocos husks. 1,8,15. ( 5 g a t h e r i n g s . )

An e s s e n t i a l l y North Temperate s p e c i e s , n o t common i n t h e t r o p i c s o r t h e s o u t h e r n hemisphere. (A,I,M; Mad; Marsh.)

P e r i c h a e n a c o r t i c a l i s (Batsch) Rost.

On very r o t t e n wood. 1. (1 g a t h e r i n g . ) Cosmopolitan. (A, I

,

^{M. 1}

P . d e p r e s s a L i b e r t

Ondeadwood. 16. ( l g a t h e r i n g . ) Cosmopolitan. ( A , I , M ; Mad; Marsh.) P h ysarum b o g o r i e n s e Racib

.

On moss on rocks and on l i t t e r under M y s t r o x y l o n , S i d e r o x y l o n and

~ r i c a l y s i a scrub. 1 , 3 , 5 , 9 , 1 0 , 1 1 . ( 7 g a t h e r i n g s . ) Widespread, b u t e s p e c i a l l y i n t h e t r o p i c s . ( A , I , M . )

P . c i n e r e u m (Batsch) P e r s .

On r o t t i n g stem of C a r i c a papaya. 1. (1 g a t h e r i n g . ) Cosmopolitan. (A, I

,

^{M. )}

P . compressum A l b . & Schw.

On r o t t i n g Agave l e a f . 1. (1 g a t h e r i n g . ) Cosmopolitan. ( A , I , M . )

P . c r a t e r i f o r m e P e t c h

On a l g a e on s t e e p rock f a c e s . 9. ( 3 g a t h e r i n g s . ) A widespread s p e c i e s , b u t nowhere common.

( ~ ~ 1 . 1

P . d i c t y o s p o r u m Martin

On u n i d e n t i f i e d l i t t e r . 12. (1 g a t h e r i n g . )

Known p r e v i o u s l y only from North America and Costa Rica ( F a r r , 1976.) T h i s s p e c i e s h a s very d i s t i n c t i v e s p o r e s b u t s u p e r f i c i a l l y resembles t h e cosmopolitan Didymium d i f f o r m e ( P e r s . ) S.F. Gray, which i s n o t y e t known from Aldabra b u t i s r e p o r t e d from S e y c h e l l e s .

P . e c h i n o s p o r u m ~ i s t e r

On l i t t e r of C a r i c a papaya, Cocos n u c i f e r a , Lumni t z e r a racemosa and T e r m i n a l i a c a t a p p a , and under dense s c r u b . 1 , 4 , 7 . ( 5 g a t h e r i n g s . ) Widespread i n t h e t r o p i c s . ( A , I ,M. )

P . g l o b u l i f e r u m ( B u l l . ) P e r s .

On Cocos husks, c a s u a r i n a l o g s and mangrove p o l e s . 1 , 9 , 1 6 . (17 g a t h e r i n g s . )

Cosmopolitan. ( 1 , M . I P. l e u c o p u s Link

On moss-covered rock under scrub. 1. (1 g a t h e r i n g . ) Cosmopolitan. ( A , I , M . )

P . m e l l e u m (Berk

.

^{& B r . ) Massee}

On l i t t e r under dense S i d e r o x y l o n s c r u b . 4. (1 g a t h e r i n g . ) Cosmopolitan, e s p e c i a l l y common i n t h e t r o p i c s . ( A I I I M . ) P . m u t a b i l e ( R o s t . ) G. L i s t e r

On l i v i n g C y p e r u s and l e a f l i t t e r of C y p e r u s , M y s t r o x y l o n and Ochna.

1 , 3 , 4 , 5 . ( 5 g a t h e r i n g s . )

S c a t t e r e d throughout t h e world, g e n e r a l l y r a r e ; recorded from South A f r i c a and S r i Lanka.

P . n i c a r a g u e n s e Macbr.

On moss-covered rock under s c r u b , and moss on Ochna t r u n k . 3,14.

(2 g a t h e r i n g s . ) Widespread i n t h e t r o p i c s , known from West A f r i c a , I n d i a and S r i Lanka; a l s o recorded from an a t o l l i n t h e C a r o l i n e I s l a n d s .

P . n u t a n s P e r s .

On wood and husks i n Cocos grove. 1 , 8 . (2 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M . )

P . o b l a t u m Macbr.

On Cocos l i t t e r . 1. (1 g a t h e r i n g . )

, Cosmopolitan. (A, I ,M - 1

P . p u s i l l u m (Berk. & C u r t . ) G. L i s t e r

On decaying s p a t h e s of Cocos. 1. (1 g a t h e r i n g . ) Cosmopolitan. ( A , I , M . )

P . r o s e u m Berk. & B r .

On Cocos husks. 1 , 8 . ( 3 g a t h e r i n g s . )

An e s s e n t i a l l y t r o p i c a l s p e c i e s . ( A I M . ) The Aldabran m a t e r i a l approaches P . p l l c h e r r i m u m Berk. & Rav. and s t r e n g t h e n s t h e view t h a t t h e two t a x a a r e c l o s e l y r e l a t e d .

serpula Morgan

On b a r k and l i t t e r o f Agave, Cocos, Mystroxylon and Sideroxylon; a c o l l e c t i o n was a l s o made on t h e l i t t e r i n an o l d n e s t of a t r o p i c b i r d (Phaethron s p . ) 1,9,12,13. ( 8 g a t h e r i n g s . )

Recorded from Yugoslavia, C e n t r a l and North America, I n d i a and Japan.

stellatum (Massee) Martin

On Cocos husks, and b a r k i n a p i l e o f mangrove p o l e s . 1.

( 5 g a t h e r i n g s . )

Widespread i n t h e t r o p i c s . (A, I ,M. 1 tenerum Rex

On cocos husks. 1 , 8 . ( 3 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M ; Marsh.)

viride ( B u l l . P e r s .

Very abundant on Cocos husks, a l s o on woody l i t t e r under Sideroxylon.

1 , 4 , 8 , 1 3 . ( 19 g a t h e r i n g s . )

Cosmopolitan. (A, I ,M ; Mad; Marsh. )

Stemoni tis f lavogeni ta Jahn

On Cocos husks and Ochna l e a f l i t t e r . 1. (2 g a t h e r i n g s . )

Probably cosmopolitan b u t r a r e l y recorded from t h e t r o p i c s . ( A , I , M . ) S. fusca Roth

On dead wood, i n c l u d i n g ?Apodytes. 4,lO. (2 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M ; Maur; Marsh.)

S. herbatica Peck

On l e a f l i t t e r of Tournefortia argentea. 1. (2 g a t h e r i n g s . ) Cosmopolitan. (A, I ,M. )

S. splendens Rost.

On r o t t i n g Casuarina log. 1. (1 g a t h e r i n g . )

Cosmopolitan. ( A , I , M ; Marsh.)

Stemonitopsis typhina ( ~ i g g e r s ) Nann. - B r a . (Comatricha typhoides ( B u l l . ) Rost. )

On decaying l o g s and Cocos husks. 1 , 4 , 8 . ( 4 g a t h e r i n g s . ) Cosmopolitan. ( A , I , M ; Marsh.)

A l l specimens were examined by b o t h a u t h o r s b u t t h e ' f i n a l d e t e r - m i n a t i o n s were t h e r e s p o n s i b i l i t y of B. Ing. Nomenclature f o l l o w s Martin ^& Alexopoulos (1969). Voucher specimens f o r a l l t a x a r e p o r t e d h e r e a r e d e p o s i t e d i n BM and K. The f o l l o w i n g a b b r e v i a t i o n s r e f e r t o t h e d i s t r i b u t i o n r e c o r d s : A

-

r e p o r t e d from t h e mainland of A f r i c a

( v a r i o u s s o u r c e s ) ; I

-

r e p o r t e d from I n d i a and/or S r i Lanka, formerly Ceylon ( v a r i o u s s o u r c e s ) ; M

-

r e p o r t e d from t h e Malesian r e g i o n ( v a r i o u s s o u r c e s ) ; Mad.

-

r e p o r t e d from t h e Malagasy Republic, f o r m e r l y

Madagascar ( P a t o u i l l a r d , 1 9 2 8 ) ; Maur.

-

r e p o r t e d f r o m M a u r i t i u s (Wiehe, 1 9 4 8 ) , and Marsh.

-

r e p o r t e d from t h e Mar'shall I s l a n d s , C e n t r a l P a c i f i c

(Rogers, 1947)

.

DISCUSSION

When c o n s i d e r i n g any i s l a n d f l o r a it i s i n t e r e s t i n g t o s p e c u l a t e on t h e b i o g e o g r a p h i c a l r e l a t i o n s h i p s w i t h t h e neighbouring i s l a n d groups and c o n t i n e n t s . I n t h e c a s e ofmyxomycete f l o r a s it would b e i n c a u t i o u s t o assume t o o much from f i e l d o b s e r v a t i o n s made over a s h o r t p e r i o d of time. Even when long-term d a t a a r e a v a i l a b l e it must be remembered t h a t w i t h e f f i c i e n t and e f f e c t i v e s p o r e d i s p e r s a l and t r a n s p o r t myxomycetes a r e n o t r e s t r i c t e d by ocean b a r r i e r s . Where t h e y occur s u g g e s t s more about t h e microecology and l o c a l c l i m a t i c c o n d i t i o n s than t h e g e o g r a p h i c a l l i m i t a t i o n s of s p e c i e s .

I n t h e p r e s e n t s t u d y t h e 55 s p e c i e s recorded i n c l u d e 40 which a r e more o r l e s s cosmopolitan, o c c u r r i n g e q u a l l y commonly i n t r o p i c a l and temperate r e g i o n s ; e i g h t s p e c i e s a r e s c a t t e r e d throughout t h e world and a r e n o t common i n any r e g i o n ; f i v e s p e c i e s a r e s c a t t e r e d i n and

r e s t r i c t e d t o t h e t r o p i c s . Two s p e c i e s were p r e v i o u s l y known from s i n g l e r e g i o n s , Didymium floccosum from t h e Mussoorie H i l l s , I n d i a , and Physarum dictyosporum from North America. I n a l l , t e n s p e c i e s a r e newly recorded f o r A f r i c a sensu l a t o .

Of t h e t o t a l , 50 s p e c i e s a r e known from I n d i a and S r i Lanka, w h i l e 43 are recorded from A f r i c a and t h e same number from t h e Malesian r e g i o n . There i s a s l i g h t s u g g e s t i o n i n t h e f l o r a t h a t t h e s p e c i e s have a c l o s e r s i m i l a r i t y w i t h I n d i a r a t h e r t h a n w i t h A f r i c a , a b i a s which may b e

s h a r e d by t h e l i c h e n f l o r a (P.W. James, p e r s o n a l communication.) The o t h e r i s l a n d groups i n t h e I n d i a n Ocean have n o t been i n t e n - s i v e l y searched f o r myxomycetes. P a t o u i l l a r d (1928) l i s t e d t e n s p e c i e s from Madagascar and a few have been added s i n c e . E i g h t o f t h e s e a r e known from Aldabra. Twelve myxomycetes a r e recorded from M a u r i t i u s

(Wiehe, 1948) o f which f i v e have been found on Aldabra. There i s one r e c o r d , o f Didymium d i f f o r m e , from t h e S e y c h e l l e s (specimen i n K. ) The o n l y o t h e r c o r a l i s l a n d s which have been i n v e s t i g a t e d a r e t h e Marshall group i n t h e C e n t r a l P a c i f i c (Rogers, 1947) where s i x t e e n

s p e c i e s a r e l i s t e d , twelve of t h e s e being found on Aldabra. F i n a l l y , t h e a t o l l s forming t h e C a r o l i n e I s l a n d s have y i e l d e d Physarum

n i c a r a g u e n s e , a l s o known from Aldabra.

The r i c h n e s s of t h e myxomycete f l o r a of Aldabra a p p e a r s t o r e s u l t from an adequate r a i n f a l l , t h e p r e s e n c e of a v a r i e d , and o f t e n deep, l i t t e r l a y e r under woody p l a n t s ( 2 6 s p e c i e s of f o l i i c o l o u s myxomycetes), t h e p i l e s o f r o t t i n g coconut husks and r e l a t e d l i t t e r (20 s p e c i e s ) and r e a s o n a b l e q u a n t i t i e s of r o t t i n g wood (15 s p e c i e s ) . These m i c r o h a b i t a t s i n t u r n r e f l e c t t h e r e l a t i v e l y s m a l l amount of human d i s t u r b a n c e of t h e i s l a n d ' s ecosystem (Beamish, 1970)

.

ACKNOWLEDGEMENTS

The f i e l d work f o r t h i s r e p o r t was c a r r i e d o u t by R . J . Hnatiuk w h i l s t D i r e c t o r of t h e Royal S o c i e t y Aldabra Research S t a t i o n i n 1973-74.

W e g r a t e f u l l y acknowledge t h e a s s i s t a n c e g i v e n by t h e Herbarium s t a f f o f t h e B r i t i s h Museum ( N a t u r a l H i s t o r y ) a n d t h e Royal B o t a n i c Gardens, K e w , and t h e f a c i l i t i e s made a v a i l a b l e t o R.J.H. by t h e Botany S c h o o l , Oxford

.

REFERENCES

Beamish, A. 1970. Aldabra alone. London, George A l l e n & Unwin.

B r a i t h w a i t e , C.J.R., T a y l o r , J . D . & Kennedy, W . J . 1973. The e v o l u t i o n o f a n a t o l l : t h e d e p o s i t i o n a l and e r o s i o n a l h i s t o r y o f A l d a b r a

.

Philosophical Transactions o f the Royal S o c i e t y ,

London. B. 266, 307-340.

F a r r , M.L. 1974. Some new Myxomycete r e c o r d s f o r t h e N e o t r o p i c s a n d some taxonomic problems i n t h e Myxomycetes. Proceedings o f t h e Iowa Academy o f Science 81, 37-40.

F a r r , M.L. 1976. Flora Neotropica, 1 6 . Myxomycetes. N e w York.

H n a t i u k , R.J. & Merton, L.F.H. 1 9 7 9 - V e g e t a t i o n o f A l d a b r a : a r e a s s e s s m e n t . A t o l l Research B u l l e t i n , 239: 1-22.

M a r t i n , G.W. & A l e x o p o u l o s , C.J. 1969. The Myxomycetes. Iowa U n i v e r s i t y P r e s s .

M a r t i n , G.W., T h i n d , K.S. & R e h i l l , P.S. 1959. The Myxomycetes o f t h e Mussoorie H i l l s ( I n d i a )

-

X. Mycologia 51, 159-162.

Nannenga-Bremekamp, N.E. 1972. N o t e s on Myxomycetes X V I I I . Proceedings o f t h e Koninklijke Nederlandse Akademie van Wetenschappen, Amsterdam, C, 75, 352-363.

P a t o u i l l a r d , N. 1928. C o n t r i b u t i o n

2

l ' g t u d e d e s champignons d e Madagascar. ~ b o i r e s de llAcademie malgache 6 , 1-49.

R o g e r s , D.P. 1947. F u n g i o f t h e M a r s h a l l I s l a n d s , C e n t r a l P a c i f i c Ocean. P a c i f i c Science 1, 92-107.

S t o d d a r t , D.R. & Mole, L.U. 1977. C l i m a t e o f A l d a b r a A t o l l . A t o l l Research B u l l e t i n 202, 1-21.

Wiehe, P.O. 1948. The p l a n t d i s e a s e s a n d f u n g i r e c o r d e d from M a u r i t i u s . Mycological Papers 24, 1-39.