KKU Journal of Basic and Applied Sciences
Journal homepage: journals.kku.edu.sa/jbas
Comparative morphological study on some Ficus species (Moraceae) in Saudi Arabia
, Mona S. Alwahibi
a, Najat Bukhari
aAndal
a- Abeer Al
Department of Botany and Microbiology, College of Science, King Saud University, P.O.Box 22452,
a
Riyadh,11495, Kingdom of Saudi Arabia.
Keywords: Ficus L., Moraceae, morphological characters, Saudi Arabia
1. INTRODUCTION
Ficus L.(Moraceae( is one of the largest and most diverse genera of angiosperms [1], consists of 750 species of trees, shrubs and climbers and its spread in tropical and subtropical regions worldwide [2, 3]. Ficus species have been used for many different purposes. The ripe fruits of F. carica and F.
sycomorus are eaten. F. microcarpia, F. elastica and F.
religiosa are used as ornamental plants. Various parts of Ficus species are used in folk medicine for their therapeutic efficacy [4]. Plants of Ficus have a special type of closed inflorescence known as syconia, which provides a suitable place for the reproduction of fig-wasps [5]. Figs and fig- wasps constitute an obligate pollination mutualism, which has attracted the attention of many biological researchers [5].
The great morphological diversity among Ficus species causes difficulties in the identification of this genus.
Therefore, there is difficulty in offering well organized classification of Ficus species. The study genus Ficus divided into four subgenera and laterally, it is classified into six subgenera [2, 6]. In flora of Saudi Arabia, Chaudhary [7]
and Collenette [8] recorded eight species, which are F.
carica, F. palmata, F. ingens, F. glumosa, F. salicifolia, F.
sycomorus, F. populifolia and F. vasta.
Phenotypic characterization is a basis step for characterizing and diagnosis of the plant species [9]. The morphological
analyses also has been performed for Ficus species [4,10- 14], So far, there is no report on a phenotypic comparison between Ficus species in Saudi Arabian. However, one recent study combing molecular and morphological analysis for three species in Saudi Arabia [15] as well as all morphological traits of Ficus species are not included in flora references, especially the flowers characters. Several Ficus species are recently introduced as ornamental plants such as F. religiosa, F. cyathistipula, F. deltoidei, F. lyrate, F.
benjamina, F. amplissima and F. binnendijkii while F.
carica is introduced as cultivars, other species are growing wild in Saudi Arabia such as F. palmata, F. sycomorus, F.
salicifolia, F. ingens, F. vasta, F. glumosa and F. populifolia.
So, this work focused on studying only seven wild species.
Therefore, the current study aimed to evaluate the phenotypic features for wild fig species in Saudi Arabia.
2. MATERIALSANDMETHODS
2.1 Plant material
This paper included seven wild taxa of Ficus L. were classified according to the recent classification of the genus [2, 16-20]. Fresh specimens were collected from several different regions of Saudi Arabia during the spring and summer seasons 2020-2021, (Table 1). Morphological characters such as the habitat, bark, stipule, leaf, syconium, and pistillate flower were studied from the materials.
Received: 25/01/2022 Revised: 10/02/2022 Accepted: 25/02/2022 Published: 28/02/2022
Abstract:
Wild Ficus in Saudi Arabia consists of seven species, which are Ficus palmata Forssk., Ficus sycomorus L., Ficus salicifolia Vahl, Ficus ingens (Miq.) Miq., Ficus vasta Forssk., Ficus glumosa Del., and Ficus populifolia Vahl. A clear understanding of the taxonomic relationships and estimate of degree of morphological variation of these species spread in Saudi Arabia are lacking. This research studied the morphology of these species using fresh specimens obtained during fieldwork to examine the degree of morphological variation in order to find out the morphological characteristics clearly for each species belonging to the genus and to study the degree of variation between them. A comparative evaluation confirmed that the species of Ficus in Saudi Arabia are effortlessly distinguishable based on numerous characters of bark, stipule, leaf, bract, ostiole, fig syconium, and pistillate flower.
Twenty-five individual trees homogeneous in growth and age of each species were selected, 10 measurements were calculated for each and an average was deduced [21].
Dissecting microscope (OPTIKA, LAB1 model, ITALIA) was used to examine the flowers and textures.
2.2 Data analysis
To evaluate the taxonomic relationship between the studied Ficus species, the XLSTAT program (version 2021.4) based on measured and descriptive characters was used and converted to a dendrogram.
3. RESULTS
3.1 Habitat
Most Ficus species are perennial evergreen trees except of F. palmata, which are deciduous shrubs or trees (Fig. 1).
3.2 Barks
Glabrous trunk bark is found in F. palmata, F. salicifolia, F.
ingens and F. populifolia, while we find the periderm peeling off, flaky trunk bark in F. sycomorus, F. vasta and F.
populifolia. Trunk color and surface of twigs bark varies for the studied Ficus species (Table 2 and Fig. 2).
3.3 Leaves
Ficus species have petiolate, simple, alternate leaves, while it is simple and sometimes palmatifid in F. palmata. The leaf shape, dimensions, apex, base and texture as shown to be varied between species. The leaf margin of Ficus species are entire, except for F. palmata which has a serrate margin.
While F. sycomorus and F. ingens leaf margins are entire- crenate. Also, the leaf petioles length and texture may vary in different Ficus species as shown in Table (3) and Fig. (3).
3.4 Stipules
Stipules are located at the top of the stem forming a terminal bud and then becoming caducous. All species of Ficus are fully amplexicaul, while it is semi-amplexicaul in F.
palmata. The shape of most Ficus species are conical, while it is deltoid in F. palmata or ovate in F. sycomorus. The texture stipule is glabrous in F. populifolia or hairy in remaining species and varies in length from 1-4 cm (Table 4 and Fig. 4).
3.5 Bracts and Ostioles
Bracts are appendages located either at the base of the receptacle, where they are called basal bracts or, surrounding aperture of the receptacle (ostiolar bracts). Ostiole bracts are present in the most of Ficus species and the numbers may vary from 3 (F. salicifola and F. ingens), 5 (F. sycomorus) or 7 (F. palmata). In F. vasta, F. glumosa and F. populifolia are absent (Table 5, Fig. 5. A and Fig. 6. A). All species have basal bracts at the fig base. The basal bracts attached at the base of the stipe in stipitate figs or at the fig base are found in F. palmata. The numbers of basal bracts ranged from 2 (F.
vasta and F. glumosa) to 3 in all other species. They can be persistent in F. palmata, F. sycomorus, F. salicifolia and F.
ingens or caducous and fall off when the fig is mature in F.
vasta, F. glumosa and F. populifolia (Table 5, Fig. 5.B and Fig. 6. B). The basal bract shape is variable between species.
It can be broadly ovate, deltoid and reniform. basal bract surface is covered with hairs in all species, but it is glabrous in F. populifolia as explained in Table (5). Some Ficus species have rounded ostiole (F. palmata, F. sycomorus, F.
salicifolia and F. ingens) or slit with 2 lips (F. vasta and F.
glumosa) and 3 lips (F. populifolia) as shown in Table (5) and Fig. (5.C).
3.6 Fig Syconia
Most of Ficus species are monoecious, while it is gynodioecious in F. palmata (Fig. 7). They are often borne in the leaf axils and in F. sycomorus on the upper part of the trunk and main branches (Fig. 8). They occur solitary or in pairs. All of the species are different pedunculate lengths (Table 6). The receptacle is pyriform, sub-globose-obovoid to sub-globose and varies in length from 0.5-2 cm in diameter. They are mostly hairy and in F. populifolia is glabrous (Table 6). The color of Syconium changed during ripening after three weeks, while it did not change in F. vasta (Table 6 and Fig. 9).
3.7 Pistillate Flowers
Pistillate flowers occur throughout the syconium except for the ostiole (Fig. 7). They vary in length of their styles and they can have long and short flowers. The long-styled flowers are mostly sessile in F. sycomorus, F. salicifolia, F.
ingens, F. vasta and F. glumosa, but F. palmata can be sessile or pedicellate (Fig. 10.A). The short-styled are pedicellate in all species and their length from 0.5-2 mm.
Ovaries of the short-styled tend to be longer than those of the long-style flowers (Fig. 10.B). The number of tepals varies from 2 to 5. The fused teplas are found in F. palmata, F.
sycomorus, F. vasta and F. glumosa and free teplas exists in F. salicifolia, F. ingens and F. populifolia. The shape of the tepal is variable between species (Table 7). All ovaries of species are superior. Ovary shape of female flowers varies in Ficus species (Table 7). Styles of species are cylindrical and lateral position. There is only one stigma and much variation exists in its shape between species of Ficus (Table 7 and Fig.
10).
3.8 Numerical Analysis of Morphological Characteristic The XLSTAT program was used to generate dendrogram depending on the morphological traits (Fig. 11) divided the 7 species into two main clusters. The first cluster contained five species, divided into two main sub-clusters. The first sub-cluster included two species (F. vasta and F. glumosa), while the second sub-cluster contained three species (F.
populifolia, F. salicifolia and F. ingens). The second cluster comprised of only two species (F. palmata and F.
sycomorus).
4. DISCUSSION
This research reviews the morphological characters of Ficus in Saudi Arabia. Diverse characters in the bark, stipule, leaf, bract, ostiole, fig syconium and female flower are useful to differentiate the species and infer relationships. F. palmata is most distinctive species in Saudi Arabia by having deciduous leaves with serrate margin, not lobbed or sometimes 2-5 lobed. The different types of leaves can be found on the same or separate branches. It is dioecious the black purple figs with basal bracts are occur at the base of the fig or present at the base of stipe in stipitate figs. This result is similar to [22, 7, 23]. The F. sycomorus is characterized by figs dull orange in panicles on the old wood, entire-crenate leaves and Stigma shape is infundibuliform.
with ostiolar bracts. This result is consistent with our study.
F. ingens is closely related to F. salicifolia by having 3 ostiolar bracts, red purple figs, and lanceolate leaves with acute-acuminate apex. It differs in the size of syconia and the leaves tend to be wide compared to those of F. salicifolia.
These results are in accordance with [25]. While F.
salicifolia is common in Saudi Arabia. It is easily distinguished from other members of Ficus by having linear lanceolate leaves with cuneate-rounded base. The same trend of results was previously reported by Bordbar and Mirtadzadini [26].
F. vasta and F. glumosa are distinctive by having slit ostiole with two lipped, two caducous basal bracts and oblique- clavate stigma shape. F. vasta can be clearly distinguished by broadly ovate-suborbiculate leaves and green figs covered with densely tomentose hairs, but in F. glumosa is characterized by elliptic leaves with rounded-shortly acuminate apex and figs are red brown. These results are in agreement with those found by Chaudhary [7] and Miller and Cope [23]. F. populifolia is rare in Saudi Arabia and distributed on Farasan Island. It is easily distinguished by having caudate apices, glabrous figs and ostiole 3-lipped.
This is in agreement with [7]. It was concluded that the differences in ostiole structure and the presence of two different types of female flowers may be due to adaptation and evolutionary history and suggest that the interaction between figs and wasps may be different [11, 27].
The constructed dendrogram based on morphological characters showed that F. vasta and F. glumosa were grouped together. The two species are classified in subgenus Urostigma [16, 19] this result comply with this taxonomy.
Similarity was observed between other taxa as: F.
populifolia, F. salicifolia and F. ingens with F. salicifolia and F. ingens closer to each other than F. populifolia. These species are placed into subgenus Urostigma [2, 17, 19] and this result was supported by this classification. Also, we noted that members of subgenus Urostigma gather in one cluster and indicates that subgenus Urostigma is monophyletic. This confirms study of Rasplus [28]. The subgenus included diversity group of monoecious species and figs borne in leaf axil with sub-globose receptacle shape.
A similar conclusion was also attained with dioecious species F. palmata belongs to subgenus Ficus [18] and monoecious species F. sycomorus is classified in subgenus Sycomorus [16], both taxa clustered in one group. This relationship was observed by Jousselin et al. [27] and Weiblen [29]. Rasplus [30] stated that monoecy character was supposed to the ancestral in Ficus and one transformed to gynodiecy in subgen. Ficus and two change to monoecy in subgen. Sycomorus. Rasplus [28] reported that two subgenus are polyphyletic and this confirms the current study. Therefore, this result was in disagreement with this classification. This study was carried out on endemic species in the region. The distinctive characteristics of the species may be compatible with other species of the same genus and may differ, but this gives a clear and original perception of the species that have been studied in Saudi Arabia.
This work indicated the importance of barks, stipules, leaves, bracts, ostioles, figs syconia and pistillate flowers in identifying and differentiating the fig species. The approach used in this work can be also useful to select highly discriminant characters in different species of genus Ficus and other woody perennial plants.
ACKNOWLEDGMENT
The authors would like to thank Deanship of scientific research in King Saud University for funding and supporting this research through the initiative of DSR Graduate Students Research Support (GSR).
Table 1: Ficus species and their collection sites
Fig. 1. habitat of Ficus species, 1. F. palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F. ingens; 5. F. vasta; 6.
F. glumosa; 7. F. populifolia.
Coordinates Name regions
Species Subgenera
18°13ʹ57.9˝ N, 42°32ʹ10.0˝ E Abha, Al Arin
Ficus palmata Forssk.
1 Subgenus Ficus Corner
19°07ʹ23.3˝ N, 42°00ʹ19.0˝ E AlMajaridah
Ficus sycomorus L.
Subgenus Sycomorus 2 (Gasp.) Miq.
18°17ʹ14.9˝ N, 42°20ʹ02.3˝ E Rajal Al-maa
Ficus salicifolia Vahl 3
Subgenus Urostigma (Gasp.) Miq.
18°93ʹ02.2˝N, 42°12ʹ19.1˝E Tanomah
Ficus ingens (Miq.) Miq.
4
17°60ʹ42.7˝N, 42°92ʹ55.5˝E Jizan, Wadi lejab
Ficus vasta Forssk.
5
17°14ʹ37.4˝ N, 43°05ʹ14.9˝ E Jizan, Jabal Fayfa
Ficus glumosa Del.
6
16°50ʹ17.6˝ N, 41°48ʹ49.7˝ E Jizan, Farasan Island
Ficus populifolia Vahl 7
Table 2: Bark characters of Ficus species
Fig. 2. Trunk bark characters of Ficus species: 1. F. palmata; 2. F. sycomorus; 3.F. salicifolia; 4. F. ingens;
5. F. vasta; 6. F. glumosa; 7. F. populifolia.
Species Trunk bark nature Trunk bark colour Color of twigs bark
Twigs bark nature
F. palmata Glabrous Grey Brown-purple Densely pubescent
F. sycomorus Periderm peeling off, flaky Creamy green Light brown Densely pubescent- tomentollus
F. salicifolia Glabrous Grey brown Brown Densely pubescent-glabrous
F. ingens Glabrous Grey brown Brown Densely pubescent
F. vasta Periderm peeling off, flaky Yellowish brown Dark brown Hirstollus F. glumosa Periderm peeling off, flaky Creamy Dark brown Densely pubescent-
tomentollus
F. populifolia Glabrous Grey brown Dark brown Glabrous
Table 3: Leaves characters of Ficus species
Petioles Lamina
Leaves type
Species Texture
Length (cm)
Surface
Base
ApexMargin
Colour
Dimensions (cm)
Shape
Densely pubescent 4
Scabrous- densely pubescent Truncate-
cordate Acute-
obtuse Serrate
Olive green 15×11
Brodaly ovate -cordate Simple-
palmatifid F. palmata
Densely tomentose 4
Scabrous- densely pubescent Cordate
Rounded- obtuse Entire-
crenate Olive
green 14×10
Ovate- elliptic Simple
F. sycomorus
Glabrous 7
Glabrous Cuneate-
rounded Acute-
acuminate Entire
Green 25×6
Linear lanceolate-
lanceolate Simple
F. salicifolia
Densely pubescent 3
Glabrous Cordate-
rounded Acute-
acuminate Entire-
crenate green
22×10 oblong
lanceolate Simple
F. ingens
Densely tomentose 10
Hirtellous - densely pubescent Cordate-
rounded Rounded-
obtuse Entire
Dark green 30×20
Broadly ovate- sub-
orbiculate Simple
F. vasta
Densely tomentose Tomentollus to 4
densely pubescent Cordate-
rounded Rounded-
Shortly acuminate Entire
Dark green 15×8
Elliptic Simple
F. glumosa
Glabrous 13
Glabrous Truncate-
cordate Caudate
Entire Dark
green 20×16
Cordate Simple
F. populifolia
Fig. 3. variations in leaves shapes of Ficus species: 1.a simple; 1.b palmatifid; 1. F. palmata; 2. F. sycomorus;
3. F. salicifolia; 4. F. ingens; 5. F. vasta; 6. F. glumosa; 7. F. populifolia.
Table 4: Stipules characters of Ficus species
Fig. 4. Variations in stipules shapes of Ficus species: 1. F. palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F.
ingens; 5. F. vasta; 6. F. glumosa; 7. F. populifolia.
Length) cm)
Texture
Shape
Stipules position
Species Semi- amplexicaul
Fully amplexicaul
2 Pubescent
Deltoid +
F. palmata -
2 Tomentose
Ovate + -
F. sycomorus
1 Pubescent
Conical -
+ F. salicifolia
1 Pubescent
Conical + -
F. ingens
4 Tomentose
Conical + -
F. vasta
3 Tomentose
Conical -
F. glumosa +
4 Glabrous
Conical -
F. populifolia + +Present; - Absent
Table 5: Bracts and ostioles characters of Ficus species
Species
Ostiolar bracts Basal Bracts Ostiole
Existence Number Position
Number Status Shape
Indumentum Shape
F. palmata Present 7 Stipe-base 3 Persistent Deltoid Pubescent
Rounded
F. sycomorus present 5 Base 3 Persistent Deltoid Pubescent
Rounded
F. salicifolia present 3 Base 3 Persistent Broadly ovate Pubescent
Rounded
F. ingens present 3 Base 3 Persistent Broadly ovate Pubescent Rounded
F. vasta Absent Absent Base 2 Caducous Reniform Densely tomentose
2-lipped
F. glumosa Absent Absent Base 2 Caducous Reniform Glabrous - densely tomentose
2-lipped
F. populifolia Absent Absent Base 3 Caducous Broadly ovate Glabrous
3-lipped
Fig. 5. Bracts and ostioles: A. 1. Ostiole rounded with seven ostiolar bracts in F. palmata; A. 2. Ostiole rounded with five ostiolar bracts in F. sycomorus; A.3. Ostiole rounded with three ostiolar bracts in F . salicifolia and F. ingens; B.1. Pedunculate fig with stipe and persistent basal bract in F. palmata; B.2.
Pedunculate fig without stipe and persistent basal bract in F. sycomorus, F. salicifolia and F. ingens; B.3.
pedunculate fig with caducous basal bract in F. vasta, F. glumosa and F. populifolia; C.1 ostiole circular pore in F. palmata, F. sycomorus, F. salicifolia and F. ingens; C.2 ostiole a slit (2-lipped) in F. vasta and F.
glumosa; C.3 ostiole a slit (3-lipped) in F. populifolia.
Fig. 6. Bracts of Ficus species: A. ostiolar bracts in F. palmata, F. sycomorus, F. salicifolia and F. ingens, B. basal bracts, at base of stipe in F. palmata, at base of fig body in F. sycomorus, F. salicifolia, F. ingens, F. vasta, F. glumosa and F. populifolia, 1. F. palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F. ingens; 5. F.
vasta; 6. F. glumosa; 7. F. populifolia.
Table 6: Figs characters of Ficus species
Species Sexuality
Fig location
Number per node Receptacle Shape Dimeter (cm) Texture Fig color before ripe Fig color after ripe Peduncle length (cm)
Leaf axils Panicles
F. palmata Gynodioecious
+ - 1-2 Pyriform 2 Pubescent Green Black purple 1.5
F. sycomorus
Monoecious
- + 1-2
Sub- globose -
bovoid o
5 Pubescent Green Reddish orange 2
F. salicifolia Monoecious
+ - 1-2 Sub-
globose 1 Pubescent Green Red purple 0.4
F. ingens Monoecious
+ - 1-2 Sub-
globose 1.5 Pubescent Green Red purple 0.4
F. vasta Monoecious
+ - 1-2 Sub-
globose 3 Densely tomentose Green Green 0.5
F. glumosa Monoecious + - 1-2 Sub-
globose 0.5 Glabrous to densely
tomentose Green Red brown 0.3
F. populifolia Monoecious
+ - 1-2 Sub-
globose 1 Glabrous Green Red purple 2
+Present; - Absent
Fig. 7. Arrangement of unisexual flowers in figs of Ficus species: (A) gynodioecious species have two kinds of figs on separate plants in F. palmata; (A.1) gall figs containing short-styled flowers and staminate flowers and (A.2) seed figs containing long-styled flowers. (B) Monoecious Ficus there is one kind of fig containing flowers with styles of varying length and staminate flowers in the remaining species.
Fig. 8. Figs location of Ficus species: A, in the leaf axil; B, on the upper part of the trunk and on main branches; 1. F. palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F. ingens; 5. F. vasta; 6. F. glumosa; 7. F.
populifolia ; 2.a panicle of figs.
Fig. 9. Figs colour before and after ripening of Ficus species: A. before ripening, B. after ripening, 1. F.
palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F. ingens; 5. F. vasta; 6. F. glumosa; 7. F. populifolia.
Table 7: Pistillate Flowers characters of Ficus species
Species
Female flowers
Tepla type Tepla number Tepla shape Position ovary Style shape Style position Stigma shape Long-styled flowers Short-styled flowers
Flower Peduncle Ovary shape Peduncle length (mm) Ovary shape
F. palmata Gamophyllous
at base 5 Linear-
lanceolate Superior Cylindrical Lateral 2 Asymmetric filiform branches
Sessile /
pedicellate Pyriform 2 Spheroid F. sycomorus Gamophyllous
at base 3 Irregularly Superior Cylindrical Lateral Infundibuliform Sessile Ovate 2 Obovate F. salicifolia Polyphyllous 4 Lanceolate Superior Cylindrical Lateral 1 Filiform branch Sessile Obovate 0.50 Obovate F. ingens Polyphyllous 4 Broadly
lanceolate Superior Cylindrical Lateral 1 Filiform branch Sessile Obovate 1.25 Obovate F. vasta Gamophyllous
at base 2 Ovate Superior Cylindrical Lateral Oblique-clavate Sessile Obovate 2 Obovate F. glumosa Gamophyllous
at base 4 Broadly
lanceolate Superior Cylindrical Lateral Oblique-clavate Sessile Obovate 1 Obovate F. populifolia Polyphyllous
4 Broadly
lanceolate Superior Cylindrical Lateral 1 Filiform branch Sessile Pyriform 1.50 Pyriform
Fig. 10. Variations in pistillate flowers of Ficus species: A. long-styled flowers; B. short-styled flowers; 1.
F. palmata; 2. F. sycomorus; 3. F. salicifolia; 4. F. ingens; 5. F. vasta; 6. F. glumosa; 7. F. populifolia; 1.a sessile flower; 1.b pedicellate flower.
Fig. 11. Dendrogram based on morphological characters of Ficus species generated using XLSTAT program.
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