, to categorize their functional relationships, and to determine if there is a specific relationship between the species and the phytotelma environment (wild and cultivated plants).
We confirm Abbe's (1935, 1938) observations that there are one primary bract
and one to three flowers in each staminate or pistillate cyme in all genera and sections of the family.
(Poinsettia "flowers" are botanically bracts
that surround the true flowers.) The range of varieties is still limited more are in the works but already they are available in both soft and vivid pinks, the latter with a neon glow.
The photosynthetic pigment including chlorophyll a (Ch a), chlorophyll b (Ch b) and carotenoid (Cr) in the bract
were determined according to the method by Wellburn (1994).
Multicategoric characters were: (1) primary head shape: round, elliptical, oval, triangular and large transverse elliptical; (2) head tip shape: pointed, round, flat and depressed; (3) external bracts
tip shape: pointed, flat and emarginated; (4) external color of the bracts
: green, violet-striped green, green-striped violet, mainly violet and totally violet; and (5) anthocyanic pigmentation of the petiole: absent, mild, partial, strong and very strong.
The surface areas of leaves and bracts
were measured using a leaf area meter (LI-3000C, Li-Cor, USA).
The most useful character to discriminate among these species corresponds to the fasciculate placement of racemes and their size, although the size and shape of bracts
, sepals and petals are also essential for their accurate identification.
2, similar to the leaves (in shape), but 1-nerved (exceptionally 3-nerved) and without foliose apex, 2.5-3.5 x 1.2-1.4 mm.
The control treatment and the treatments stored at 12 and 19[degrees]C for two, four, six and eight days did not lead to an alteration in bract
color of the inflorescences, as indicated by the [L.sup.*], [a.sup.*] and [b.sup.*] colorimetric variables (Table 4).