Revision of the group previously known as Panicum L. (Poaceae: Panicoideae) in Madagascar
Author
Vorontsova, Maria S.
text
Candollea
2018
2018-11-05
73
2
143
186
journal article
20513
10.15553/c2018v732a1
025e1235-99de-4ef9-8849-de54ad29a779
2235-3658
5724514
15.
Panicum ibitense
A. Camus
in
Bull. Soc. Bot.
France
72: 371. 1925
(
Fig. 6B
,
9
).
Lectotypus
(designated here):
MADAGASCAR
.
Prov. Antananarivo
:
Mont Ibity
,
I.1914
,
Perrier de la Bâthie
10771
(
P
[
P00450269
]!;
isolectotype
:
K
[
K000244700
]!,
P
[
P00450270
]!,
TAN
[
TAN000389
]!,
US
[
US00147890
]!)
.
Scandent ascending perennial, with wiry branching stems and an underground bulb
5–8 mm
in diameter, to
70 cm
long, with glabrous stems and nodes, the nodes enlarged near the base and sometimes finely pilose when young.
Leaf sheaths
glabrous.
Ligule
membranous, truncate.
Leaf blades
linear, flat or rolled, firm, 1–8 ×
0.1–0.4 cm
, glaucous, dehiscing at the base of the leaf sheaths, scaberulous on both sides.
Panicles
terminal, fully exserted,
10–20 cm
long, ovate, the branches wiry, glabrous.
Spikelets
ovate, apically obtuse,
1.5–2 mm
long, brown to purple, partly open at maturity.
Lower glume
3/4–4/5 as long as the spikelet, truncate to obtuse, with fine cilia at the apex, 3–5-veined, with small prickle hairs on the upper part.
Upper glume
as long as the spikelet or sometimes 3/4 of the spikelet length, herbaceous, 5-veined, with small prickle hairs on the upper part.
Lower floret
male, with palea.
Lower lemma
herbaceous, 5-veined, with small prickle hairs on the upper part.
Upper lemma
smooth, shiny, pale.
Distribution and ecology
. – Endemic to Madagascar’s southern High Plateau (a single collection known from northern
Madagascar
), common in the frequently burned tapia forest and in open rocky habitats, often on quartz,
800 –1800 m
(
Fig. 8B
).
Notes
. – This species is unique among Madagascar’s grasses in its unusual adaptation to fire: bases of the culms thicken into woody perennial nodule-like storage organs below the ground. The young plant has short flat leaf blades along the culm which dehisce early, leaving only the wiry stems and inflorescences visible for most of the year. Spikelets also dehisce early. The long lower glume, almost as long as the spikelet, is a useful character for identification.
The
Gautier 3011
record from Manongarivo is surprising and seems doubtful. This collection does not have an underground storage organ which could be due young plant age; the late post-flowering stage of the spikelets also decreases reliability.
Other species named after Mount Ibity use the epithet
“ibityense”
but this was published as
“ibitese”
and may not be corrected according to Art. 60.9 (
TURLAND et al., 2018
).
The
lectotype
sheet is chosen for its best quality material and annotation by the author.
Additional material examined
. –
MADAGASCAR
.
Prov. Antananarivo
:
PK 40 rte d’Arivonimamo
,
V.1960
,
Bosser
14450
(
P
[
P02608818
],
TAN
)
;
ibid. loco
,
V.1962
,
Bosser
15596
(
P
[
P02325449
],
TAN
)
;
60 km
on rte de Miarinarivo
,
V.1962
,
Bosser
16003
(
P
[
P02608815
],
TAN
)
;
Ambohimanga
,
27.III.1921
,
Decary
159
(
P
[
P02608848
])
;
ibid. loco
,
27.III.1921
,
Decary
162
(
P
[
P02608808
])
;
ibid. loco
,
27.III.1921
,
Decary
165
(
P
[
P02608847
]
;
Ibity Massif
,
15.II.2003
,
Schatz
et al. 4036
(
P
[
P02309339
],
TAN
)
;
ibid. loco
,
17.II.2003
,
Schatz
et al. 4108
(
K
[
K000805609
],
P
[
P06795901
])
.
Prov. Antsiranana
:
Manongarivo Reserve
,
en-dessous d’Ambalafary
,
14°04'S
48°17'E
,
8.IV.1996
,
Gautier
3011
(
G
,
K
[
K000805463
],
P
[
P06795994
],
TAN
)
.
Prov. Fianarantsoa
:
entre Ambatofinandrahana et Itremo
,
IX.1956
,
Bosser
9780
(
TAN
)
;
45 km
avant Ambositra
,
XII.1963
,
Bosser
18750
(
P
[
P02608814
],
TAN
)
;
Ranohira
,
Isalo
,
PK 713
,
III.1964
,
Bosser
19125
(
P
[
P02608816
],
TAN
)
;
Itremo
,
IV.1964
,
Bosser
19562
(
P
[
P02608812
],
TAN
)
;
54 km
E of Ambatofinandrahana
,
25.I.1975
,
Croat
29644
(
TAN
)
;
pentes occidentales à Faliarivo
,
III.1934
,
Humbert
14502
(
P
[
P02608809
])
;
plateaux et vallées de l’Isalo
,
29.I.1955
,
Humbert
29 757
(
P
[
P03487887
],
TAN
)
;
montagnes à l’W d’Itremo
,
Humbert
30077
(
P
[
P02608806
])
;
ibid. loco
,
17.I.1955
,
Humbert
30080
(
G
,
P
[
P02608844
],
TAN
)
;
Itremo
,
Ambatoantrano
,
20°34'11"S
46°34'51"E
,
17.III.2013
,
Nanjarisoa
&
Andriamampionona
49
(
K
,
TAN
)
;
Itremo
,
Ampangabe
,
20°36'41"S
46°36'34"E
,
15.II.2014
,
Nanjarisoa
et al. 114
(
K
,
TAN
)
;
Itremo
,
Soatsihotapaka
,
20°31'33"S
46°34'54"E
,
20.II.2014
,
Nanjarisoa
et al. 153
(
K
,
TAN
)
;
Itremo
,
Ianasana
,
20°34'41"S
46°35'05"E
,
13.III.2012
,
Ratovonirina
et al. 171
(
K
,
TAN
[
K000753861
])
;
ibid. loco
,
13.III.2012
,
Ratovonirina
et al. 189a
(
K
,
TAN
[
K000753879
])
;
Isalo
,
1.7 km
from Namaza camp on the trail to the Blue and Black Pools
,
22°32'15"S
45°22'31"E
,
17.XII.2013
,
Vorontsova
et al. 1315
(
TAN
)
;
Itremo
,
Ambatoasira
,
20°36'44"S
46°34'26"E
,
20.V.2014
,
Vorontsova
et al. 1582
(
TAN
)
;
Itremo
,
IV.1921
,
Waterlot
106
(
P
[
P02608846
])
.
Prov. Toamasina
:
près de la gare de Masse
,
Bosser
16588
(
P
[
P02608820
],
TAN
)
;
Ambatovy
,
I.1972
,
Bosser
21115
(
P
[
P06795997
])
;
ibid. loco
,
V.1969
,
Morat
3245
(
P
[
P02307366
])
;
Mangoro
,
II.1925
,
Perrier de la Bâthie
16886
(
P
[
P02608845
])
;
Ambatovy
,
18°48'48"S
48°19'40"E
,
23.II.2005
,
Rakotovao
et al. 1362
(
K
[
K000805485
],
P
[
P06768481
])
;
Ambatovy
,
commune rurale Ambohibary
,
18°51'14"S
48°18'50"E
,
22.II.2005
,
Razanatsoa
et al. 244
(
G
,
P
[
P06768480
])
.