| Data Species | Hair density | Hair wall | Hair vestibule | Basal form |
| H. arbainense | Dense | Smooth | Hollow | Oval |
| H. longiflorum | Dense | Rough | Absent | Rounded |
| H. petrocarpum | Low | Smooth | Hollow | Oval |
| H. strigosium | Dense | Rough | Filled | Oval |
| H. zeylanicum | Low | Rough | Filled | Globose |
| H. jizanense | Low | Smooth | Hollow | Circular |
| H. lasiocarpum | Low | Rough | Filled | Absent |