i854 A TEXTBOOK OF THEORETICAL BOTANY 



The genus Sanicida contains some forty cosmopolitan species though 

 none is found in Australia. The flowers are formed in cymose umbels and 

 the fruits are hooked, being adapted for animal distribution. The sepals 

 are better developed in this genus than in most and are slightly imbricated. 



In the genus Astrantia (Fig. 1759) the simple umbel is enveloped in 

 large, coloured involucral bracts, which increases greatly the attractive 

 appearance of the inflorescence. 



The third sub-family, the Apioideae, is by far the largest, containing 

 many common herbs, some of which have already been mentioned. It is 

 impossible to consider even all the common genera here. We may note a 

 few which are of economic importance. Apium graveolens has been culti- 

 vated and improved to provide the common vegetable Celery. Daiicus 

 carota is the wild plant from which all the long- and stump-rooted carrots 

 have been derived. Both the above occur wild in Europe and western Asia. 

 Pastinaca sativa, also native of Europe and Asia, has given us the Parsnip. 

 All these are naturally biennials, producing their storage roots and radical 

 leaves in the first year and developing their flowering spikes at the expense of 

 reserve food stores in the second year. The seeds of various species are 

 also used, chiefly in cooking. Caraway seeds come from Cariim carvi; Dill 

 seeds from Peucedaniim graveolens; Coriander seeds from Coriandrimi 

 sativum; and Anise from PimpineUa anisiim. Fennel, which is used in 

 flavouring soups, is obtained from the leaves of Foenicuhim capillaceum; 

 while Gum Ammoniacum is a resin obtained by puncturing the stem of 

 Dorema afumoniaciim. Conium maculatiun, which is found wild in Britain, is 

 the source of the alkaloid drug coniine, which is derived from the seeds. 

 It has been known from early times as Hemlock. 



The pollination mechanisms exhibited by members of the family as a 

 whole fall into a number of distinct types, most of which are found in the 

 sub-family Apioideae. 



1. Flowers almost homogamous 



This type we have already referred to, since it is best illustrated by 

 Hydrocotyle vulgaris. 



2. Strongly marked protandrous dichogamy 



This is probably by far the most common in the family. The inflores- 

 cences rather than the individual flowers attract insects, which attraction is 

 enhanced by an ethereal secretion which is noticeable to the insect. The 

 nectar is completely exposed, and is secreted on a disc in the centre of 

 the wide-open flower and is therefore accessible to quite small flies. The 

 stamens develop first and the anthers have discharged all their pollen well 

 before the flowers of the same umbel have spread their styles and developed 

 their stigmas. Thus self-pollination is entirely excluded. 



3. Andromonoecism 



In this type both male and hermaphrodite flowers are present, and the 

 male flowers often have longer stalks than the hermaphrodite ones. This \ 



type is well illustrated by Torilis, Astrantia, Anthriscus and Scandix. 



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