Many people living in tropical and subtropical climates have
observed orange growths on plant leaves, stems, even cement
block walls. These growths are often identified as filamentous
algae in the order Trentepohliales. Their life styles vary from
free-living forms found on many surfaces in wet, humid areas,
to damaging plant parasites. Though they belong to the division
of aquatic green algae (Chlorophyta), the Trentepohliales
are aerial, needing free water only to germinate. Their color
varies from yellow-green to bright orange, depending on the
amount of carotenoid pigment produced. All are autotrophic.
Cephaleuros is the best known genus in the order, with early
reports of severe damage to tea and coffee plantations in 19th-
At present there are six recognized genera in the Trentepohliales:
Cephaleuros Kunze in Fries, Stomatochroon Palm, Phycopeltis
Millardet, Physolinum Printz, Trentepohlia Maritius, and
Printzina Thompson and Wujek. Cephaleuros is a plant parasite,
living under the leaf cuticle of its host (Figure 1a).
Stomatochroon is only present in the substomatal chambers of
leaves (Figure 1b). Phycopeltis (Figure 1c) and Physolinum
usually live on leaves but may be found on other surfaces in
humid environments. Trentepohlia (Figure 1d) and Printzina
grow on living and non-living substrates