P.holttumii is closely related to P.grande ,P.superbum, and P.wandae. It differs from the first two by having fertile fronds with two lobes, one smaller and elevated, the other larger and hanging down. Both lobes have spore patches. It differs from P.wandaeby not having the little points on the edges of the shield fronds around the bud
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n nature P.holttumiiis from bright locations in monsoon forests. This indicates it should be given high light, and kept more moist during its growing season. P.holttumiicannot be expected to take the low temperatures given for P.superbumotherwise they may be treated the same.
P.holttumiiwhich shows two fertile fronds, each with a smaller lobe that is elevated, and with a larger lobe that hangs down.
In the 1970 paper which separated P.grandeand P.superbumJoncheere and Hennipman described P.holttumiias a new species. It is named for Dr. R. E. Holttum, of England,
P.holttuniiis found in Cambodia, Laos, Vietnam, Malay Peninsula, and in Thailand, from 0 to 700m. (0 - 2,200 ft.) It is found in Thailand growing with P.wallichii.
In practice it can be very difficult to tell P. holttumiifrom P.wandae. Since their fertile fronds are about the same shape, the little frills on the shields at the bud of P.wandae become the main distinguishing feature. In a P.wandaewith old shields, its little frills may die back, causing it to look like P. holttumiiuntil new shields form.