THE DICOTYLEDONES 1903 



Lycium, Atropa, Hyoscyamus, Physalis, Capsicum, Solanum, 

 Mandragora. 

 3. Datureae. Ovary four-chambered, the walls of the loculi dividing 

 the placentae equally. Datura, Solandra. 



II. Cestroideae 



The embryo is either straight or if curved the curvature is less than a 

 semi-circle. 



I. Cestreae. Androecium of five stamens, all of which are functional. 

 Cestnim, Nicotiana, Petunia (Fig. 1822). 



Fig. 1822. — Petunia " hybrida " of gardens. 

 The garden forms are mostly hybrids of 

 P. nyctaginiflora and P. violacea. 



2. SaJpiglossideae. Androecium of five stamens, only two or four of 

 which are fertile and these are always of unequal length. Sal- 

 piglossis, Schizanthus, Brunfehia. 



The Solanoideae are by far the larger of the two sub-orders and include 

 most of the genera of economic importance. Solatium is the largest genus 

 with about 1,200 species, most of which are herbs. The corolla is rotate 

 and the fruit a many-seeded berry. The anthers form a cone in the centre 

 of the flower and dehisce by apical pores. The pollination is sometimes 

 eflFected by bees. In 5. tuberosum (Fig. 1823) the flowers are white or pale 

 violet and are erect by day but droop by night. When the flower is visited 

 the stigma is touched first, hence favouring cross-pollination. There is 

 however no nectar and the quantity of pollen is small. Selt-poUination 

 therefore is customary and it appears to be eftected either by the folding 

 of the corolla or by curvature of the style which brings it into the line of 

 falling pollen. In S. dulcamara there are capitate projections on the recep- 

 tacle which occur in pairs at the base of the corolla lobes. Like the recep- 

 2E 



