132 Plants and their Ways in South Africa 



Dianthus (Carnation), Datura, and Hibiscus the sepals have 



grown together, forming a cup. 



Within the calyx, the second row of flower leaves is the 

 corolla, or little crown. It 

 is usually the showy part of 

 the flower. Sometimes the 

 calyx is brightly coloured, 

 and may at first be mistaken 

 for the corolla. Calyx and 

 corolla taken together make 

 the perianth. 



The third whorl bears 



FIG. us. Crassuia centauroides, Httle resemblance to leaves. 



Thunb. (From Edmonds and Mar- Tt rnndctc nf ac manv cl^nH^r 

 loth's " Elementary Botany for South ll conslsts ot as man Y slender 



Africa".) threads as there are petals ; 



each thread ends in a yellow knob. They are the stamens. 

 The thread of the stamen is the filament (thread), and the 

 knob the anther. The anther contains the powder-box, and 

 each box contains very valuable powder, called pollen (micro- 

 spores). In the centre of the flower are several boat-shaped 

 bodies, tapering to a point. They are the pistils or carpels. 

 The lower part of the pistil is the ovary. It contains small 

 rounded bodies, the ovules, which are destined to form seeds. 



Structure and Forms of Ovules. The ovule consists 

 of a mass of cells, the nucellus, surrounded by one or two 

 seed-coats ; two integuments (or coats) are found as a rule in 

 Monocotyledons and Archichlamydeae T (Umbelliferae and Le- 

 guminosae may be noted as exceptions) and one in Sympetalae. 

 The place of attachment of nucellus and seed-coat is called 

 the chalaza. The stalk is known as the funicle, and the 

 scar formed on the seed at its place of attachment to the ovary, 

 the hilum. 



The simplest form is the straight or orthotropous ovule. 

 The funicle, chalaza, and micropyle lie in a straight line. It 

 may be found in the orders Commelinacea, Xyridacece, Poly- 

 gonacece, Restiacea. A second form found in Mulberry and 

 Fig is known as amphitropous. The nucellus is straight but 



1 A subdivision of Dicotyledons. See Engler's " System of Classifi- 

 cation," p. 209. 



