The comparative study of Alkanna and Huynhia (Boraginaceae, Lithospermeae), with description of a new species in Iran
Author
Khalvati, Sina
0000-0002-1782-6672
Department of Biology, Herbarium Division, Bu-Ali Sina University, P. O. Box 65175 / 4111, Hamedan, Iran. & sinakhalvati @ gmail. com; https: // orcid. org / 0000 - 0002 - 1782 - 6672
sinakhalvati@gmail.com
Author
Ranjbar, Massoud
0000-0003-0939-3878
Department of Biology, Herbarium Division, Bu-Ali Sina University, P. O. Box 65175 / 4111, Hamedan, Iran. & ranjbar @ basu. ac. ir; https: // orcid. org / 0000 - 0003 - 0939 - 3878
ranjbar@basu.ac.ir
text
Phytotaxa
2021
2021-11-09
524
4
216
234
journal article
3654
10.11646/phytotaxa.524.4.1
c7ecb63e-4d46-4af3-b512-cb76ba9e0caa
1179-3163
5656352
2.
Alkanna semiromica
Ranjbar & Khalvati
,
sp. nov.
Fig. 10
.
Type:
—
IRAN
.
Isfahan
:
Semirom
,
31°25’ 0.01”N
,
51°34’0.01”E
,
2950 m
,
30 April 2012
,
Ranjbar 30880
(
holotype
BASU
!).
Fig. 11
.
Diagnosis:
—The new species is similar to
Huynhia pulchra
, but differs by its smaller cauline leaves (
1.2–2 cm
versus
3–5 cm
), pedicel in fruiting state (up to
8 mm
versus up to
5 mm
), blue to light violet corolla (versus sulphur yellow with purple spots), shorter corolla (
12–14 mm
versus
18–20 mm
), calyx in flowering state (
7–10 mm
versus
8–14 mm
), shorter style
5–7 mm
(versus
9–10 mm
) and stigma shallowly bilobed (versus deeply bilobed). The pollen grains are ovoid and 3-colporate, in contrast to prolate and stephanocolporate pollen in
H. pulchra
. Pollen characters fit
Alkanna
, in where the new species is similar to but differs from
A. frigida
. It differs by corolla dark blue (versus sulphur yellow), shorter basal leaves (8–15 ×
0.5–1 mm
versus 30–100 ×
5–12 mm
) and narrow corolla limbs (versus broad limbs).
Etymology:
—The specific epithet refers to Semirom, a city in
Isfahan province
, where the new species was found.
Description:
—Perennial green plant, with stout scaly stock. Stem multi-branched, branched from base, densely patent-pilose. Basal leaves, oblong to ovate, 8–15 ×
0.5–1 cm
, acute to subacute, tapering into the petiole, with entire, flat, or sometimes slightly undulate margins, white setose, sometimes with prominent base. Cauline leaves, oblong to lanceolate, 1.2–2 ×
0.3–0.5 mm
, acute or subacute, sessile, attenuate at base, with an evident midrib, veinless, densely white setose.
Inflorescence a compact terminal head; 2–3 ×
1.5–3 cm
, pedicels short, leafy, peduncle
1–2 cm
long; bracts oblong to ovate, 12–15 ×
3–5 mm
. Calyx
7–10 mm
long in flower, up to
15 mm
long in the fruiting state, broad at nearly the base; lobes linear to lanceolate, acute, densely hispid-setose with yellowish, patent setae up to
2 mm
long. Corolla blue to violet light, lobes
12–14 mm
long, loosely pubescent outside, slightly pilose inside, slightly constricted below the anthers. Annulus absent. Stamens inserted irregularly at different levels; three higher at the throat and two lower down in the middle of the tube. Anthers
1.5–2 mm
long. Style
5–7 mm
long, reaching up to the middle of the corolla tube, shallowly bilobed; lobes
0.2 mm
long. Nutlet not seen.
Palynology:
—Pollen grains heteropolar, triangular concave, tricolporate, equatorial axis (E) 9.3 ± 1.9 μm, polar axis (P) 11.5 ± 3.85 μm, ornamentation psilate.
Fig. 5
.
Distribution and ecology:
—
Alkanna semiromica
was seen in the field by the first author and is known from a single specimen from the
type
locality that is deposited at the herbarium of Bu-Ali
Sina
University (BASU). The new species occurs in
Isfahan province
. It is endemic to southwestern
Iran
and known only from the
type
locality. It was collected from the rocky terrain along the roadside of the Black Mountains.
IUCN Red List category:
—A low frequency of the new species in one field locality was observed and therefore decided to classify this species as VU (Vulnerable). This category includes taxa with small populations that could be at risk, according to IUCN criteria (
IUCN, 2001
). We revisited the locality, where the new species was discovered and the neighboring areas in 2019. Our interpretation is based on a single known population.
Pollen morphology:
—Members of the family
Boraginaceae
represent a great array of pollen
types
, and thus the family is interesting for investigating the evolution of pollen characters (
Noroozi et al 2021
). Pollen characters can provide other elements with taxonomic significance can play important role in diversification of the group. According to previous studies, the pollen morphology of the
Huynhia
has been described as radial symmetric, isopolar with prolate shapes, polycolpate
types
, and with psilate ornamentations (
Tab. 1
;
Coppi
et al.
2015
,
Khatamsaz 2001
). The pollen grains of the new species were observed as triangular concave and 3-colporate, which fits the ancestral state of the
Lithospermeae
and is realized in the genus
Alkanna
(
Noroozi
et al.
2021
)
. The average polar axis (P) was between 11.5–15.35 μm and the average equatorial axis (E) between 9.3–11.19 μm. From this palynological information we infer the taxonomic placement of the new species in the genus
Alkanna
.
FIGURE 10.
Alkanna semiromica
(
Ranjbar 30880
).
A
) habit;
B
) stem & inflorescence;
C
) corolla;
D
) calyx;
E
) style. Drawn by: S. Khalvati.
FIGURE 11.
Alkanna semiromica
Ranjbar & Khalvati
(
Ranjbar 30880
, BASU).
TABLE 1.
Main pollen characters of
Huynhia pulchra
,
H. purpurea
and
Alkanna semiromica
.
Species
|
P (μm)
|
E (μm)
|
P/E
|
Shape
*
|
Aperture
|
Aperture No.
|
H. pulchra
|
28.45 ± 3.93 |
17.6 ± 0.84 |
1.61 ± 0.14 |
P |
stephanocolporate |
8 |
H. purpurea
**
|
34 |
24 |
1.41 |
ell |
stephanocolporate |
6/7 |
A. semiromica
|
11.5 ± 3.85 |
9.3 ± 1.89 |
1.23 ± 0.14 |
tc |
tricolporate |
3 |
* p: prolate; ell: elliptical; tc: triangular concave
** Data taken or adapted from
Coppi
et al.
2015
(
2015
).
Taxonomic discussion:
—The specimens kept at BASU,
M. Ranjbar 30880
, were determined morphologically as
H. pulchra
(Willdenow ex Roemer & Schultes) Greuter & Burdet
, which are confined to
Isfahan province
. Herbarium material of this species is very scarce. However, when the specimens were more thoroughly examined, several characters appeared to be dissimilar to that species and other closely related species. The new species is similar to
H. pulchra
, especially by its habit, indumentum, number of leaflets, and shape, size, and arrangement of pods, and also differs from
H. pulchra
, by pollen shape, stigma shallowly bilobed, shorter style, smaller corolla, and calyx in anthesis. General and detailed characters of the vegetative parts and flowers in
Huynhia
are already well known from various literature. Here, two characters are worthy of mention because of their taxonomic significance; one concerning the androecial arrangement and other the stigma structure. In
Huynhia
the epipetalous stamens are inserted through very short filaments at different heights within the corolla tube, e.g., three higher at the throat and two lower down in the tube, however, this character also occurs in
Alkanna frigida
(
Khatamsaz 2002
)
(
Fig. 12
). Given the payonlogical evidence from above, the new Iranian blue to light violet-corolla species is fully described here as a new species and named as
Alkanna semiromica
.The differences in characters of the new species and its relatives are shown in
Table 2
.