THE LOWER DICOTYLEDONS. 335 



the fruit ; each is called a vitta (Fig. 136). The ripe meri- 

 carps dangle on the slender stalks and are readily detached 

 and carried away by wind. Their flat form, giving a large 

 surface without increase of weight, is an admirable adapta- 

 tion for wind dispersal. The seed is endospermic, the endo- 

 sperm being hard and oily. 



CARPOPHORE ^.---STIGMA 



MERICARP 



V1TTAE' 



RIBS 



Fig. 136. Schizocarp of Heracleum (Cow Parsnip). 



344. The Umbellifer Family (Umbelliferae) is a fairly 

 large one, chiefly found in the North Temperate region and 

 well represented in Britain. Most Umbellifers can be recog- 

 nised by the hollow stems, alternate sheathing pinnate leaves, 

 compound umbels, and characteristic splitting fruit. In 

 a few cases, e.g. Hydrocotyle, there is a simple umbel ; in 

 Sanicle there is a cymose grouping of simple umbels; in 

 Eryiigium the flowers are in a head. 



The general flower structure is practically the same through- 

 out the Order, and the Umbellifers are classified chiefly on 

 the structure of the fruit, so that except in the case of such 

 readily recognised plants as Cow Parsnip, Hydrocotyle, 

 Sanicle, Eryngium, etc., it is necessary to have ripe fruits 

 in order to identify an Umbellifer species in a " Flora." 

 The outer surface of each half -fruit usually has 5 projecting 

 ridges, in some cases with secondary ridges, 4 to each half- 

 fruit, between the primary ones. It is important also to 

 note the appearance of the vittas, and the breadth of the 

 surface of junction between the two half -fruits. 



345. Water Pennywort (Hydrocotyle), a small creeping plant in 

 wet places, has round peltate leaves and simple umbels of small 

 greenish or pinkish white firs. (May-July). Wood Sanicle (Sani- 



