The seed atlas of Pakistan-XI. Urticaceae

Abstract

Seed morphology and its numerical analysis of the 9 taxa belonging to the family Urticaceae carried out with the help of scanning electron microscopy. Seed micro and macro morphological characters were significantly helpful to trace the phenetic relationship between the taxa of the family Urticaceae.

Full text

Pak. J. Bot., 47(3): 987-994, 2015.
THE SEED ATLAS OF PAKISTAN-XI. URTICACEAE
RUBINA ABID
*
, AFSHEEN ATHER AND M. QAISER
Department of Botany, University of Karachi, Karachi-75270, Pakistan.
*
Corresponding author’s e-mail: rubinaku@yahoo.com
Abstract
Seed morphology and its numerical analysis of the 9 taxa belonging to the family Urticaceae carried out with the help
of scanning electron microscopy. Seed micro and macro morphological characters were significantly helpful to trace the
phenetic relationship between the taxa of the family Urticaceae.
Key words: Seed morphology, Phenetic relationship, Urticaceae, Pakistan.
Introduction
The family Urticaceae is commonly known as
Nettle family, comprises 1050 species distributed in 48
genera mostly found in tropical regions few species are
also reported from temperate zones (Mabberley, 2008).
In Pakistan the family Urticaceae is represented by 9
species distributed in 6 genera viz., Forsskalea L.,
Lecanthus Wedd., Parietaria L., Pilea Lindl., Pouzolzia
Gaudich and Urtica L. including 9 taxa (Ghafoor, 1981).
There are various reports available where seed
morphological data was significantly used to reveal the
taxonomic as well as phylogenetic relationship of the
taxa (Ather et al., 2010; Rajbhandary & Shrestha, 2010;
Kanwal et al., 2012; Abid et al., 2013; Ather et al.,
2013). Previously seed morphology of the Nettle family
have been studied by few workers (Berggren, 1981;
Boufford, 1997; Chen et al., 2003; Kirkbride et al.,
2006; Bojnans & Fargasova, 2007) but no detailed
report is available on the seed morphology of the family
Urticaceae from the area under consideration. The seed
morphological characters are analysed numerically to
find out the relationship of the taxa within the family
Urticaceae from Pakistan.
Material and Methods
Mature and healthy seeds of 9 taxa of the family
Urticaceae were collected from the herbarium
specimens. Mostly 10 plants/species and 10 seeds/plant
were studied (Appendix-I) and examined under
stereomicroscope (Nikon XN Model), compound
microscope (Nikon type 102) and scanning electron
microscope (JSM-6380A). For scanning electron
microscopy dry seeds were directly mounted on metallic
stub using double adhesive tape and coated with gold for
a period of 6 minutes in sputtering chamber and
observed under SEM. The terminology used is in
accordance to Lawrence (1970), Radford et al. (1974)
and Stearn (1983) with slight modifications. Numerical
analysis was carried out to recognize the relationship
and dissimilarities of species within the family
Urticaceae. Hierarchical clustering was performed by
using Euclidean distance index with the computer
package (Anon., 2012). Each taxon was treated as
operational taxonomic unit (OTU). Macro and micro-
morphological characters of seeds viz., size, shape,
colour and surface patterns were used. Characters were
recorded as presence or absence and coded as 1 or 0
respectively (Tables 2, 3) and the average values of the
quantitative characters viz., seed length and breadth
were directly used (Tables 2, 3).
Observations
General seed characters of the family Urticaceae
Seeds 0.5-2.5x0.1-1mm, ovate, obovate, oblong,
elliptic or broadly elliptic, dark brown, light brown,
yellowish, off-white with or without orange patches or
black, shiny or unshiny, surface rugose, colliculate,
apressedly colliculate, psilate, ruminate, foveate,
foveolate, striate or sparsely tuberculate, hilum basal
(Table 1. Figs. 1-8).
Represented by 6 genera viz., Forsskalea L.,
Lecanthus Wedd., Parietaria L., Pilea Lindl., Pouzolzia
Gaudich, Urtica L.
Key to the genera
1 + Seeds elliptic, oblong or obovate .……..……………………………….……..…………………………………. 2
- Seeds broadly elliptic or ovate. ……………………………………..……..………..…………………………… 5
2 + Seeds black …………………………………………………………………………………………………..…... 3
- Seeds brown or off-white ……………………………………………………………..…………………………. 4
3 + Seeds c. 0.5mm long, surface colliculate …………………………………...………….….……...…… Lecanthus
- Seeds c. 1.5mm long, surface psilate ……………….………………………………………….…….... Parietaria
4 + Seeds c. 2.5mm long, dark brown …………………………………………..……................................ Forsskalea
- Seeds c.1.2mm long, light brown or off-white ………………………….…………...……….………… Pouzolzia
5 + Seed surface sparsely tuberculate or foveated ………………….…………….………..……………………. Pilea
- Seed surface colliculate or foveolate ………………….……………………….………………….……….. Urtica

RUBINA ABID ET AL.,
988
Fig. 1. Scanning electron micrographs. Forsskalea tenacissima: A, seed; B, surface. Lecanthus peduncularis: C, seed; D, surface.
Parietaria judaica: E, seed; F, surface. Pilea scripta: G, seed; H, surface. P. umbrosa: I, seed.
(Scale bars: C=500 µm; A=200 µm; E, G, I=100 µm; B=50 µm; D, F, H=10 µm)

THE SEED ATLAS OF PAKISTAN-XI. URTICACEAE
989
Fig. 2. Scanning electron micrographs. Pilea umbrosa: A, surface. Pouzolzia hirta: B, seed; C, surface. P. pentandra: D, seed; E,
surface. Urtica dioica: F, seed; G, surface. U. pilulifera: H, seed; I, surface. (Scale bars: H=200 µm; B, D, F=100 µm; A, C, E=10 µm;
G, I=50 µm)

RUBINA ABID ET AL.,
990
Fig. 3. Dendrogram showing the relationship of the species within the family Urticaceae.
Fig. 4. Bar diagram showing the variation in the length(mm) of
the seeds within the family Urticaceae.
Fig. 5. Bar diagram showing the variation in the breadth (mm) of the
seeds within the family Urticaceae.
Parietaria judaica
Forsskalea tenacissima
Lecanthus peduncularis
P. umbrosa
Pilea scripta
Pouzolzia hirta
P. pentandra
Urtica dioica
U. pilulifera

THE SEED ATLAS OF PAKISTAN-XI. URTICACEAE
991
Fig. 6. Bar diagram showing the variation in the seed shapes of
the family Urticaceae.
Fig. 7. Bar diagram showing the variation in the seed colours of
the family Urticaaceae.
Fig. 8. Bar diagram showing the variation in the seed surfaces of
the family Urticaaceae.
Forsskalea L.
Seeds 2.5x1mm, elliptic, dark brown, surface rugose,
hilum basal.
Represented by a single species viz., Forsskalea
tenacissima L.
Lecanthus Wedd.
Seeds 0.5x0.1mm, elliptic, black, surface colliculate,
hilum basal.
Represented by a single species viz., Lecanthus
peduncularis (Royle) Wedd.
Parietaria L.
Seeds 1.5x0.8mm, elliptic, black, shiny, surface
psilate, hilum basal.
Represented by a single species viz., Parietaria
judaica L.
Pilea Lindl.
Seeds 1.2x0.8mm, broadly elliptic or ovate, off-white
or yellowish, surface foveate or sparsely tuberculate,
hilum basal.
Represented by 2 species viz., Pilea scripta Wedd.,
P. umbrosa Blume.
Appendix-I. List of voucher specimens.
S. No. Taxa Collector, number and herbarium
1. Forsskalea tenacissima M. Qaiser et al. 7224 (KUH); Nazim et al. 119 (KUH); S.M.H. Jafri 2714 (KUH);
Y. Nasir 32 (KUH); A. Ghafoor & Steve M. Goodman 4926 (KUH); T. Ali & G.R.
Sarwar 2639 (KUH); T. Ali 952 (KUH); Shams-ul-Islam 26 (KUH).
2. Lecanthus peduncularis S. Abedin & M. Qaiser 8731 (KUH).
3. Parietaria judaica T. Ali et al. 2229 (KUH); Haider Ali 392, 2464 (KUH); Haider Ali & Jan Alam
1278 (KUH); Jan Alam 124 (KUH); S.W. Khan & Lalmast Khan 386 (KUH).
4. Pilea scripta S. Abedin 7665, 8460 (KUH); Saida Qureshi 35, 208 (KUH).
5. P. umbrosa Y. Nasir & Khan 1105 (RAW); M. Qaiser & A. Ghafoor 5014, 5071, 5274 (KUH);
Saida Qureshi 195 (KUH).
6. Pouzolzia hirta M. Qaiser & A. Ghafoor 4924 (KUH).
7. P. pentandra M. Qaiser & A. Ghafoor 4611 (KUH); Saida Qureshi 271 (KUH).
8. Urtica dioica S. W. Khan 6 (KUH); M. Qaiser & Rizwan Yusuf 7729, 7924 (KUH).
9. U. pilulifera Rizwan Yusuf Hashmi 181, 198 (KUH); M. Qaiser & A. Ghafoor 5194 (KUH).

RUBINA ABID ET AL.,
992
Table 1. Seed morphological characters of the family Urticaceae.
Name of taxa Size (mm) Shape Colour Surface Hilum
Length Breadth
Forsskalea tenacissima 2.5 1 Elliptic Dark brown Rugose Basal
Lecanthus peduncularis
0.5 0.1 Elliptic Black Colliculate Basal
Parietaria judaica 1.5 0.8 Elliptic Black, shiny Psilate Basal
Pilea scripta 1.2 0.8 Broadly elliptic Off-white Sparsely tuberculate Basal
P. umbrosa 1.2 0.8 Ovate Yellowish Foveate Basal
Pouzolzia hirta 1.2 0.8 Oblong Off-white Ruminate Basal
P. pentandra 1.2 0.8 Obovate Light brown Striate Basal
Urtica dioica 1 0.8 Broadly elliptic Off-white with
orange patches
Appressedly
colliculate Basal
U. pilulifera 1.5 1 Ovate Off-white Foveolate Basal
Key to the species
1 + Seeds broadly elliptic and sparsely tuberculate …………………………..……….................................. P. scripta
- Seeds ovate and foveated ………………..………………………………………............................…. P. umbrosa
Pouzolzia Gaudich
Seeds 1.2x0.8mm, oblong or obovate, off-white or
light brown, surface ruminate or striate, hilum basal.
Represented by 2 species viz., Pouzolzia hirta (Blume)
Hassak., P. pentandra (Roxb.) Benn.
Key to the species
1 + Seeds oblong and ruminate…………………………………………………………...………………..… P. hirta
- Seeds obovate and striate ……………….………………………………………….….……...…….. P. pentandra
Urtica L.
Seeds 1-1.5x0.8-1mm, broadly elliptic or ovate, off-
white with or without orange patches, surface foveolate or
appressedly colliculate, hilum basal.
Represented by 2 species viz., Urtica dioica L. and
U. pilulifera L.
Key to the species
1 + Seed surface apressedly colliculate ………………….…………...………………….…..…………….... U. dioica
- Seed surface foveolate ………………….………………………..…………………………….…….. U. pilulifera
Results and Discussion
Seed morphological data is found to be useful to
correlate with the gross morphology. The dendrogram
based on the seed morphological characters of the taxa
belonging to the family Urticaceae clearly revealed the
presence of two distinct groups A and B. Group A
comprises three genera viz., Lecanthus, Parietaria and
Forsskalea with elliptic, black or dark brown seeds and
plants with dot like cystoliths (Ghafoor, 1981) While,
the genera of group B viz., Pouzolzia, Pilea and Urtica
are characterized by the presence of broadly elliptic,
oblong, ovate, obovate, off-white, yellowish and light
brown seeds and plants with linear cystoliths (Ghafoor,
1981). Moreover within the first group Lecanthus and
Parietaria are coupled together by having black seeds,
male flowers with more than one stamen and female
flowers with calyx, however Forsskalea falls separately
and is distinct with dark brown seeds, male flowers with
only one stamen and female flowers without calyx.
Within the second group Pouzolzia pentendra falls
separately by having light brown, obovate seeds. While,
the remaining three species of the group B viz., Pilea
scripta, Pouzolzia hirta and Urtica dioica share the
common cluster by having off-white, yellowish, broadly
elliptic and oblong seeds with dioecious plants (Ghafoor,
1981). While, ovate seeds and monoecious or rarely
dioecious plants (Ghafoor, 1981) have been observed in
Pilea umbrosa and Urtica pilulifera. Thus it is evident
that seed characters are significant enough to correlate
the taxonomic delimitation within the family Urticaceae.
Acknowledgement
This research work is a part of the project “The Seed
Atlas of Pakistan” sponsored by HEC, which is gratefully
acknowledged. Thanks are due to the Director, Center for
Plant Conservation for providing the facilities of scanning
electron microscopy.

THE SEED ATLAS OF PAKISTAN-XI. URTICACEAE
993
Table 2. List of characters, scored for cluster analysis for the taxa of Urticaceae listed in Table 1.
Character description
1. Length (mm)
2. Breadth (mm)
Shapes
3. Elliptic: absent (0), present (1)
4. Broadly elliptic: absent (0), present (1)
5. Ovate: absent (0), present (1)
6. Obovate: absent (0), present (1)
7. Oblong: absent (0), present (1)
Colour
8. Light brown: absent (0), present (1)
9. Dark brown: absent (0), present (1)
10. Black: absent (0), present (1)
11. Off-white with orange patche: absent (0), present (1)s
12. Off-white without orange patches: absent (0), present (1)
13. Yellowish: absent (0), present (1)
Surface
14. Rugose: absent (0), present (1)
15. Colliculate: absent (0), present (1)
16. Appressedly colliculate: absent (0), present (1)
17. Psilate: absent (0), present (1)
18. Sparsely tuberculate: absent (0), present (1)
19. Foveate: absent (0), present (1)
20. Foveolate: absent (0), present (1)
21. Ruminate: absent (0), present (1)
22. Striate: absent (0), present (1)
Hilum
23. Basal: absent (0), present (1)
Name of species 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Forsskalea tenacissima 2.5 1 1 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1
Lecanthus peduncularis 0.5 0.1
1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 1
Parietaria judaica 1.5 0.8
1 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 1
Pilea scripta 1.2 0.8
0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1
P. umbrosa 1.2 0.8
0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 1 0 1
Pouzolzia hirta 1.2 0.8
0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 1
P. pentandra 1.2 0.8
0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
Urtica dioica 1 0.8
0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1
U. pilulifera 1.5 1 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 1
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(Received for publication 28 February 2014)