Total evidence phylogeny of Pontederiaceae (Commelinales) sheds light on the necessity of its recircumscription and synopsis of Pontederia L.
Author
Pellegrini, Marco O. O.
Author
Horn, Charles N.
Author
Almeida, Rafael F.
text
PhytoKeys
2018
108
25
83
http://dx.doi.org/10.3897/phytokeys.108.27652
journal article
http://dx.doi.org/10.3897/phytokeys.108.27652
1314-2003-108-25
613AFFC18E03FFDEFFA1DB2FFF88FFAE
1409868
5.
Pontederia L. subg. Pontederia
Fig. 9
Michelia
Adans., Fam. Pl. 2: 201. 1763, nom. illeg. Type species (designated here).
Pontederia cordata
L.
Narukila
Adans., Fam. Pl. 2: 54. 1763, nom. illeg. Type species (designated here).
Narukila cordata
(L.) Nieuwl. (≡
P. cordata
L.).
Pontederaea
Kuntze, Revis. Gen. Pl. 2: 718. 1891, orth. var.
Pontederas
Hoffmanns., Verz. Pfl.: 137. 1824, orth. var.
Reussia
Endl., Gen. Pl.: 139. 1836. Type species (designated by
Lowden 1973
).
Reussia triflora
Endl.
ex
Seub. [≡
P. triflora
(Endl.
ex
Seub.) G.Agostini et al.].
Unisema
Raf. Med. Repos. 5: 352. 1808, nom. illeg. Type species.
Unisema obtusifolia
(Raf.) Raf. (≡
P. cordata
L.).
Umsema
Raf. Med. Repos. 5: 352 1808, orth. var.
Unisemma
D.A.Godron, in Orbigny CVD, Dict. Univ. Hist. Nat.: 761. 1848, orth. var.
Description.
Herbs
perennial or annual, aquatic to amphibious, erect-emergent or procumbent-emergent.
Rhizome
short and generally inconspicuous.
Stems
erect or trailing, spongy, unbranched to branching only at the base to branched.
Sessile leaves
early deciduous.
Petiolate leaves
distichously-alternate, evenly distributed along the stem or congested at the apex of the stem, emergent, ligule truncate, petioles not-inflated, blades cordate to broadly cordate, rarely elliptic to lanceolate or narrowly ovate.
Main florescences (inflorescences)
terminal, sessile or pedunculate; inflorescence leaf without an inflated leaf-sheath; basal bract flat; cincinni alternate, 1-3-flowered, sessile to shortly-pedunculate, internodes contracted.
Flowers
sessile, tristylous, zygomorphic, non-enantiostylous, perianth connate forming a tube, infundibuliform, revolute at post-anthesis, non-deliquescent and loosely enclosing the developing fruit, lobes 3 superior and 3 inferior, rarely 5 superior and 1 inferior, the central superior lobe with a nectar guide, consisting of 2 yellowish-green to green spots, generally surrounded by a dark purple to bluish-purple, rarely white blur, coiling or post-anthesis; stamens dimorphic, filaments free from each other, J-shaped, glandular-pubescent, anthers dorsifixed, rimose; ovary with 1 fertile locule, 1-ovulate, septal nectaries present, style glandular-pubescent or glabrous, stigma truncate or capitate or trilobate.
Achene
ovoid or pyriform; anthocarp hardened, ridged, ridges sinuate, toothed or echinate.
Seeds
curved narrowly ovoid or ovoid, testa smooth.
Figure 9.
Pontederia L. subg. Pontederia
.
A-C
habit:
A
dense population of
P. parviflora
Alexander
B
population of
P. ovalis
Mart.
ex
Schult. & Schult.f.
C
habit of
P. rotundifolia
L.f.
D-E
petiolate leaves:
D
blade of
P. rotundifolia
E
blade of
P. parviflora
F-H
inflorescences:
F
inflorescence of
P. cordata
L., showing flowers with two yellow nectar guides in the posterior perianth lobes
G
inflorescence of
P. parviflora
, showing flowers with a sole yellow nectar guide in the posterior perianth lobes
H
inflorescence of
P. rotudifolia
, showing a lilac-flowered form
I
oblique view of a flower of
P. ovalis
J-K
fruits:
J
detail of the apex of the infructescence of
P. ovalis
, showing the anthocarp with sinuate ridges
K
detail of an achene of
P. cordata
, showing the toothed ridges.
A
by C. Willig & L. Nusbaumer
B, I, J
by M.O.O. Pellegrini
C
by L.O.A. Teixeira,
D, H
by R. Aguilar
E
by M.R. Engels
F
by Ashitaka-f Studio
G
by M.V. Lameiras and
K
by A. Haines.
Circumscription.
Pontederia subg. Pontederia
is circumscribed by us to comprise eight species. Our concept of
P. subg. Pontederia
is equivalent to the concept of
Pontederia
adopted by
Lowden (1973)
. Nonetheless, we accept
P. triflora
as distinct from
P. subovata
and increase the number of species in the
P. cordata
complex by the re-establishment of
P. ovalis
. The members of this subgenus are peculiar within
Pontederia
s.l.
due to their spike-like main florescences, ovaries 1-locular by abortion, fertile locule 1-ovulate, pendulous placentation, fruit an achene, hardened and ornate anthocarps and smooth seeds.
Distribution.
Exclusively Neotropical.