656 



BOTANY 



PART II 



runners from ancient times. M. crispa, another commonly cultivated form, is a 

 crispate variety of M. viridAs ; M. longifolia, var. undulata, M. sylvestris, etc. 



Official. — Eosmarinus officinalis yields oleum rosmarini. Lavandula vcra^ 

 (Mediterranean region), oleum Lavandulae. Mentha 2M^erita, oleum menthae 

 PIPERITAE. M. viridis, oleum menthae vikidis. 31. arvensis and M. 2n2Krita 

 yield menthol. Thymus vulgaris and Monarda 2yundata yield thymol. 



Order 6. Personatae 



The Personatae are connected by the small family Nolanaceae to 

 the Convolvulaceae, from which the Tubiflorae are also derived. The 

 flowers are actinomorphic or zygomorphic. Their typical form has 

 also the floral formula K 5, C (5), A 5, G (2). There are, however, 

 no false septa in the ovary, and the number of ovules is usually a 

 larger one. 



Family 1. Solanaeeae. — Herbs or small woody plants, with alter- 

 nate, exstipulate leaves and nearly always actinomorphic flowers. 



Corolla expanded or tubular ; petals plaited 

 in the bud. Ovary bilocular, septum inclined 

 obliquely to the median plane. Ovules numer- 

 ous, on a thick placenta (Fig. 697). Fruit, a 

 capsule or a berry. Seeds with endosperm ; 

 embryo usually curved. 



Family generally distributed, especially in tropical 

 America. In many Solanaeeae, as will be further re- 

 ferred to in the -special descriptions below, the inflores- 

 cences exhibit apparent extra-axillary branches and 

 paired leaves. Anatomically the order is characterised 

 by possessing bicollateral vascular bundles. 



Important Genera and Species. — (a) Fruit, a berry : The Deadl)'- Nightshade 

 {Atropa Belladonna, Fig. 698) is a perennial herb of shrubby habit, springing from 

 an underground rhizome. It is a native of Europe and western Asia, occurring in 

 less dense woods. The shoots are, to begin with, orthotropous and radial, and 

 bear alternate leaves and a terminal flower, which only rarely produces fruit. 

 Below this terminal flower branching and the development of leaves commences 

 in, as a rule, three equally vigorous, lateral shoots. Each lateral branch, with its 

 further cincinnal branching, forks and assumes a dorsiventral habit. By the pre- 

 dominance of one of the two axillary shoots and the carrying up of the subtending 

 bract upon it, the terminal flower at each grade of branching becomes apparently 

 axillary. The large, subtending bract is borne up beside the smaller one belonging 

 to the next higher axillary bud, which is usually undevelojied, so that the leaves 

 appear to be borne in pairs. Flower with a short, wide, tubular corolla of a dirty 

 jiurple colour. Calyx enlarging after fertilisation beneath the bluish-black fruit ; 

 the position of the obliquely placed septum of the latter is recognisable externally 

 by the presence of a shallow groove. 



Many species of Solanum occur as weeds. Flowers actinomorphic. S. niijrum, 

 Nightshade ; *S'. dulcamara, Bitter-sweet (Fig. 699), is a shrubby plant, climbing by 

 means of its stems and petioles, and especially common in thickets by the l)anks 

 of streams and similar situations. ,S'. tuberosum, the potato. Lyco2)ersicum, the 



Fig. 697— Solanaeeae. Floral 

 diagram (_Petunia). 



