20.

Stems usually with the cataphylis deciduous or weathering into a mass of fibers, sometimes persisting intact; leaf blades usually thick, the minor veins conspicuous or not; upper blade surface usually lacking visible raphide cells; spathe usually curved forward and somewhat hooding the spadix; spadix with tepals various but not usually thickened and glossy.
section Belolonchium

Note: section Episeiostenium Schott is omitted as it is a seemingly unnatural group and no definitive characteristics have been determined for its separation. Of all the sections presented by Engler this is the least likey to be a valid one. Already half the species assaigned to this group by Engler have unequivocally been placed in other sections includieng the section Pachyneurium . The secton will not be further discussed in this paper. The numbering of the sections have been changed from an earlier version of this paper to reflect what we believe to be a more accurate arrangement. For example, sect. Digitinervium is moved to near Porphyrochitonium to which it is clearly more related.

SECTIONS OF ANTHURIUM

I. TETRASPERMIUM Schott (Fig. 1-3)
This small section consists of plants which are usually somewhat scandent with slender stems and generally long internodes (Fig. 2 & 3). The cataphylls are usually thin and decompose but persist at least at the terminal nodes (Fig. 1 & 3). Leaf blades are generally more or less elliptic and acute at the base usually with numerous primary lateral veins. One or both surfaces of the blade are conspicuously glandular-punctate (with dark dots). The spadix is usually small (generally short) and the berries have 4 or more seeds. The best example of the section is the very common Anthurium scandens  (Aubl.) Engl. which ranges throughout the American tropics. The section Tetraspermium  is uniquely based on 2N = 24, except for A. tonduzii  Engl. with 2N = 30. Polyploid is a prominent feature of A. scandens  of 2N = 24, 48, 84 and for A. trinerve  Miq. of 2N = 24 found in Central America and 2N = 30 found in Surinam.

The section Tetrspermium appears to be a very natural section but is one of the smallest with probably fewer than eight species. Sheffer and Kamemoto (1976) attempted numerous interspecific hybridizations using A. scandens  and A. trinerve  as pollen parents, but none has resulted in hybrids. Due to the unique chromosome number, the inability of A. scandens  and A. trinerve  to form hybrids with other Anthurium species would be anticipated. Anthurium scandens and A. trinerve cannot easily be used as maternal parents, since they are apparently self-pollinating or apomictic (i.e., capable of producing seed without any form of fertilization or sexual union).

II. GYMNOPODIUM Engl. (See Exotica 3, P. 132)
This section is based on a single rare species from western Cuba, Anthurium gynnopus  Griseb., and is characterized by its somewhat scandent habit, elongate internodes, deciduous cataphylls and subcoriaceous, suborbicular leaf blades. It is also characterized by its long inflorescence with a long-stipitate spadix. The most important character is that the berries

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