Revisional study of neotropical Beilschmiedia species (Lauraceae ...

16), B. ovalis (Fig. 18), B. peruiula (Fig. 19), B. rigida (Fig. 20), B. stricta(Fig. 23) andB.
taubertiana (Fig. 24). Most of these species have the tertiaries random reticulate.
Ramification. Roth ( 1996) called an area surrounded by a delicate network of a minor
venation "mesh". Meshes are various in size and shape, sometimes divided into smaller
meshes. She recognized two types of meshes, "open" meshes and "closed" meshes. In open
meshes the bundle ramifications terminate freely within the meshes, while in closed meshes
no free endings are developed within the meshes.
In neotropical Beilschmiedia species, the most discriminating character of the
ramification is the extent of the hierarchy of mesh subdivision, rather than whether meshes
are open or closed.
In most species, larger meshes are divided further into smaller meshes, and the
smallest meshes can be open or closed even in the same leaf (but see below).
Compared to the difference between the open and closed meshes, two patterns are
more clearly recognizable in the degree of their mesh division. In some species the larger
meshes are divided several times and the smallest meshes formed by the veins in the sixth or
higher order. In other species larger meshes are divided only once or twice, and the smallest
meshes are formed by the veins in the fourth and fifth order. The appearance of the leaf in
the former case is "flne ramification", whereas the appearance in the latter case is "coarse
ramification" (these terms are original for this study). The appearances are so different that
one can recognize them with the unaided eye.
Fine ramification occurs in B. alloiophylla (Fig. 26) B. anay (Fig. 27), B. costaricensis
(Fig. 32, but see below), B. hexanthera (Fig. 35), B. immersinervis (Fig. 37), B. latifolia
(Fig. 38), B . mexicana (Fig. 40), B . obovatifolia (Fig. 42),B. ovalioides (Fig. 43),B. ova/is
(Fig. 44), B . pendula (Fig. 45), B. riparia (Fig. 47), B. steyermarkii (Fig. 48) and B.
tovarensis (Fig. 51). The smallest meshes are less than 0.5 mm in diam. Among the species,
B. costaricensis and B. pendula usually have slightly coarser (c.a. 0.5 mm in diam.)
ramification than the other species (c.a. 0.2 mm in diam.). These species also have the
ramification square-like with angular meshes, whereas the other species have the one areole
with more or less roundish n1eshes. And in B. costaricensis there are some collections which
appear to have coarser ramification (but see the discussion). Many species with fme
ramification have their smallest meshes more or less closed, whereas B. costaricensis, B.
hexanthera and B. pendula have the smallest meshes open.
110