Photo from Google
The P. wallichii is named for Nathaniel Wallich, Director of
the Calcutta Botanical Garden in 1815
Common name is Indian Staghorn, they are found in the wild in Thailand, Northern India, Burma and the Yunnan Privince of China.
This species has tall spreading shields with many rounded lobes along their upper edge. It forms a definite basket. The shields may all be brown while the fertile fronds are still green.
The fertile fronds have distinctively prominent veins on the upper side. Their shape varies greatly in cultivation. Although there is one main lobe which hangs down and has the main spore patch on in, there may be a second lobe to it's side with a spore patch, with third lobe to it's side with no spore patch. If there are enough lobes, the frond becomes fan-like and the outer lobes may even blend in with the shields. The area with the spore patch extends forward and may have points on the edge. The three lobes are labeled A, B, C in photo on right. This photo also shows blotched shield fronds that no one has discussed in publications. Are they dirt stains or typical markings on all P. wallichii? Observing Google images suggests they may be common markings on P. wallichii.
Roy Vail's photo on left shows a fertile frond with many lobes. Only the first two have spore patches. This fertile frond is so wide that it has formed a curtain in front of the shield fronds. Notice the distinctively prominent veins on the upper side.
P. wallichii is difficult to grow in collections. It may die from rots, but more often it goes into dormancy and never comes out. There are different ideas on how to prevent dormancy. One grower gives it no water while dormant. Another grower keeps it watered well all year so it does not go dormant. More experience with this species is needed and there are too few growers of P. wallichii.
P. wallichii growing in Thailand grow together with P. holttumii and share the same environment, monsoon forests with definite wet and dry seasons. Roy Vail thinks possibly cool temperatures during dormancy are important to these plants.
Roy feels the future of P. wallichii in the hobby probably depends more on sporelings being raised under cultivation here than on imports. These plants could be better conditioned to the environment in collections. The spore are green, an indication they do not live long. They germinate quickly. Sporelings, under very moist conditions, have volunteered, causing Roy to suggest that a pad of moist moss kept below a spore patch might develop some sporelings.