Codiaeum variegatum : Forms & Sizes

Codiaeum variegatum (L.) Blume, commonly known as “croton”, is an ornamental shrub that originates in tropical forests.

A wide range of variations in leaf shape and coloration has fascinated breeders, landscapers, horticulturists and gardeners, and a huge number of cultivars have been fixed for commercial production. More than 300 cultivars are available in the ornamental horticulture industry.

Diversity in croton’s leaf-shape is quite enormous. The leaf shapes include ovate to linear, entire to deeply lobed, appendiculateat the middle connected by midrib. Coloration and color pattern on the leaves is also a prominent characteristic to distinguish each cultivar.

The phenotypic diversity observed in croton leaves is of a great interest in plant science because virtually all types of leaf morphology can be seen in one species; the plasticity in leaf phenotype is extremely high.

It appears that genetic instability is associated with the leaf phenotypic diversity. Somatic mutations and/or cross pollination by ants may be involved in the mechanism for creating such high diversity. 

A high variation in chromosome numbers and karyotypes may attribute to the morphological diversity among the cultivars of this species.

Croton cultivars can be devided into groups based on leaf types:

1.  Slender

2. Oval

3. Curly

4. Lobed

5. Interrupted

  

Source:

Mollick A.S, et al., 2011, Croton Codiaeum variegatum (L.) Blume cultivars characterized by leaf phenotypic parameters, Scientia Horticulturae Volume 132, 5 December 2011, Pages 71-79.

Plumeria rubra : Forms & Sizes

The estimated number of Plumeria species ranges from five (Wiersema, 2008) to 45 (Llamas, 2003).

In 1938, R.E. Woodson organized P. rubra into four forms delineated by the primary colors of the flowers: white, yellow, pink, and a tricolor.  Today, many hundreds of variations of these four forms exist.

Hortus Third (Bailey and Baley, 2000), recognized the four forms of P. rubra as described by Woodson.

Plumeria rubra f. acutifolia has white flowers with yellow centers.

Plumeria rubra f. lutea has yellow flowers fading to white at the edge as they mature.

Plumeria rubra f. rubra has pink flowers of varying intensity with a tangerine-yellow center.

Plumeria rubra f. tricolor has pale yellow-white flowers with tangerine-yellow centers and red or pink rim.

Source : Stephen H. Brown, Identification of the Four Forms of Plumeria rubra, Proc. Fla. State Hort. Soc. 121:406–407. 2008.

Momordica charantia : Forms and Sizes

Bitter gourd ( Momordica charantia ) comes in a variety of shapes and sizes, with colour ranging from green to white.

The cultivar common in China ( M. charantia forma charantia ) is 20–30 cm long, oblong with bluntly tapering ends and pale green in color, with a gently undulating, warty surface.   

The Indian variety ( M. charantia forma abbreviata ) has a narrower shape with pointed ends, and a surface covered with jagged, triangular "teeth" and ridges.

  

Between these two extremes are any number of intermediate forms.  Some bear miniature fruit of only 6–10 cm in length.