Characters

P. arabicus

P. asirensis

P. barbatus

P. cylindraceus

P. hijazensis

P. pseudomarrubioides

P. tenuiflorus

Seed morphology

1. Seed shape (mm)

Sub spherical

Ovoid

Ovoid

Sub spherical

Ovoid

Sub spherical

Sub spherical

2. Seed size

0.7 - 0.8 × 0.6 - 0.7

1.3 - 1.5 × 1.1 - 1.2

1.2 - 1.5 × 0.8 - 1

0.7 - 0.8 × 0.6 - 0.7

1.1 - 1.5 × 0.7-1

0.6 - 0.7 × 0.5 - 0.6

0.8 - 1 × 0.7 - 0.9

3. Seed color

Reddish-brown

Reddish- brown

Black

Yellow- brown

Reddish- brown

Yellow-brown

Reddish-brown

Pollen morphology

4. Polar axis (P μm)

(20 - 26) 23

(22 - 30) 26

(26 - 36) 31

(20 - 26) 23

(21 - 25) 23

(16 - 24) 20

(37 - 44) 41

5. Equatorial diameter (E μm)

(15 - 21) 18

(20 - 25) 22

(20 - 28) 24

(15 - 21) 18

(13 - 16) 15

(14 - 18) 16

(26 - 32) 29

6. P/E

1.28

1.18

1.29

1.28

1.5

1.25

1.41

7. Pollen shape

Subprolate

Subprolate

Subprolate

Subprolate

Prolate

Subprolate

Prolate

8. pollen type

Hexa- Zonocolpate

Hexa- Zonocolpate

Hexa- Zonocolpate

Hexa- Zonocolpate

Hexa- Zonocolpate

Hexa- Zonocolpate

Hexa- Zonocolpate

9. Exine sculpture

Bi-reticulate

Bi-reticulate

Primary lumina is reticulate and secondary is granulate- perforate

Bi-reticulate

Primary lumina is reticulate and secondary is microreticulate

Primary lumina is reticulate and secondary is microreticulate

Primary lumina is reticulate and secondary is microreticulate

Trichomes morphology

10. Unbranched multicellularhairs

+

+

+

+

+

+

+

11. Bi-cellular hairs

+

-

-

+

-

-

-

12. Branched multicellular hairs

+

-

-

-

-

-

-

13. Multicellular glandular hairs

+

-

-

-

-

-

-

14. Long-stalked capitate hairs

-

-

-

-

+

-

-

15. Peltate hairs

-

-

-

+

+

-