"Dear friends
Most of us know through Floras and common books Callistemon lanceolatus DC. as the commonest species of Callistemon cultivated in many parts of India. As it turned out for last 5 to six decades this was considered as synonym of C. citrinus (Curtis) Stapf.
As has been clearly specified in Trees of Delhi (Pradip Krishen) none of the specimens grown in Delhi belong to C. citrinus. They actually belong to C. viminalis (Soland. ex Gaertn.) Cheel., the two similarly looking species are distinguished as under:
C. viminalis: Tree with drooping slender branches; leaves linear-lanceolate, up to 10 cm long and 4-7 mm broad; flowers scarlet--red in up to 7 cm long dense spikes; filaments united at base; fruits not persisting on old wood.
C. citrinus: Shrub or tree with short arching branches; leaves broadly lanceolate, rigid, up to 7 cm long, 6-12 mm broad; flowers scarlet red in up to 10 cm long spike; filaments free at base; fruits persisting on 2--3 year old branches.
Now there is a big catch. It has now been established (both on The Plant List and GRIN) that C. lanceolatus (Sm.) Sweet and C. citrinus (Curtis) skeels are two distinct species and not synonymous (although C. lanceolatus DC. a synonym of latter). It would as such be interesting to know the differences between the two to be able to place our specimens properly. Perhaps some member can help.
I also have feeling that C. rigidus of
Flowers of India and one uploaded by
Aarti ji from Lalbagh may actually be one of these two species, as C. rigidus has much narrower almost linear lobes and capsules with almost close mouth where as in both above uploads leaves are broader almost broadly lanceolate with capsules with clearly open mouths.
Perhaps once differences between C. lanceolatus and C. citrinus as understood now, are know, we can place our specimens correctly. "