342 PLANTS OF NEW ZEALAND 



Convolvulaceae, 



THE BINDWEED FAMILY. 



Distribution. A large family, chiefly tropical. The large rhizomes 

 frequently contain an acrid, milky juice, sometimes used for medicinal purposes. 

 The flowers are usually large and ornamental. The Kumara or Sweet Potato, 

 which was introduced into New Zealand in very early times, belongs to this 

 family. From the roots of Exogonium, jalap is obtained. 



Key to the Genera. 



1. Stems leafy, prostrate or twining- 2 

 Stems leafless, twining, parasitic. Cuscuta, p. 344. 



2. Corolla plaited. Style 1. 3 

 Petals overlapping in bud. Styles 2. Dichondra, p. 344. 



3. Stigmas 2. 4 

 Stigma 1-, 2-, or 3-lobed- *Ipomcea. 



4. Ovary imperfectly 2-celled. Bracts large, 



enclosing the calyx. Calystegia p. 342. 



Ovary 1-celled, bracts small or wanting. Convolvulus, p. 342. 



* Not further described. 



Genus Convolvulus. 



Perennial herbs, with milky juice, climbing by means of their twining stems. 

 Flowers funnel-shaped, white, pink, or rarely blue. Sepals 5 ; corolla 5-angled. 

 Stamens 5. Fruit a capsule. 1 sp. 



Convolvulus erubescens (The Blushing Convolvulus). 



Stems prostrate, 2 in. -12 in. long, never twining. Leaves variable in shape, 

 usually oblong-hastate or cordate. Flowers white. In Australian specimens 

 they are often rose-coloured. Both islands, in dry places. Fl. Nov. -Dec. 



The species of this genus and the next are often widely 

 distributed. C. erubescens is closely allied to the English 

 C. arvensis, and is found chiefly on dry hill sides. It is common 

 near Sumner (Christchurch) . Calystegia sepium is another 

 plant, which, though sometimes rose-coloured elsewhere, is 

 always white in New Zealand (cf. Wahlenbergia) . The 

 name erubescens therefore, as applied to our species, is not 

 significant. 



Genus Calystegia. 



Closely allied to the previous genus, and sometimes united with it, but 

 distinguished by the characters given in the Key to the Genera. 4 sp. 



Many species are cultivated for their large showy flowers. 

 In the bud, the corolla is spirally twisted. The anther lobes, 



