430 



FERTILIZATION AND FORMATION OF FRUIT IN PHANEROGAMS. 



ripening, and only later, when the seed is ripe, do they separate from one another, 

 as though the original fruit had been cut into its component parts by a sharp knife. 

 Each of these components (known as Mericarps) remains indehiscent like an achene, 

 and is distributed with its contained seed. As a type of these schizocarps the 

 Mallow (Malva) may be taken. In the Umbelliferae the two mericarps into which 

 the schizocarp splits remain for a long time suspended from the tips of a forked 

 prolongation of the axis, as in the fruits of the Caroway (Carum carvi, fig. 322 ''), 

 Parsley (Petroselinum, fig. 322 *^), and Fennel (Foeniculum, fig. 322 ^). 



As already mentioned, the pericarp of many indehiscent fruits assists in the 

 dispersal and establishment of the inclosed seeds. This may happen in two ways. 

 The surface of the fruit may bear hairs, curved bristles, or hooked spines which 

 become attached to the coats of animals ; or wings, plumes, &c. may be produced, 

 allowing the fruit to be readily borne away even by the gentlest of breezes. Such 

 winged fruits are termed Samaras, and many forms of them are distinguished by 

 the descriptive botanist. To these remarkable fruits, however, we shall return in 

 detail later on when dealing with the dispersal of plants; it will suffice here to indi- 

 cate briefly a few forms. The fruits of the Ash (Fraxinus excelsior) are shown in figs. 

 323 1, 2. 3, 4-) ipi^g pericarp of each consists actually of two carpels joined together; it is 

 continued into a well-marked membraneous wing. Fig. 323 '' repi-esents the samara 

 of the Tree of Heaven (Ailanthus glandulosa) which is continued below and above 

 the seed-containing portion into a thin, spirally-twisted wing. In the fruit of the 

 Umbelliferous Angelica sylvestris (fig. 323 ^) each half (mericarp) shows a sinuous 

 wing-like fringe on either side, whilst in Banisteria (fig. 323 ^) there projects from 

 the back of each component a membraneous continuation resembling a butterfly's 

 wing. 



Dry dehiscent fruits are also known as Capsules. When ripe their pericarp, 

 which is quite dry, opens and liberates the seeds in a vai'iety of ways.' The empty 

 capsule remains, as a rule, on the parent plant, or comes away in pieces (valves) at 

 the time of dehiscence. In neither case, however, has the pericarp any further con- 

 cern with the seeds after these are once liberated. These capsules are the commonest 

 class of fruit, and as their structure is characteristic of many genera, their various 

 modifications have received distinctive names. When the pericarp arises from a 

 single carpel, and at ripening opens along one side, along the so-called ventral 

 suture, whilst the opposite side (the dorsal suture) is unsplit, or but partially, one 

 speaks of the fruit as a Follide. As a rule several follicles are collected together 

 in a cluster at the end of the flower-stalk, as, for instance, in Monkshood (Aconitum) 

 and in the Star Anise (Illicium anisatum, cf. fig. 325^); more rarely are they 

 solitary, as in certain species of Larkspur (Delphinium). In the Proteacese, also, 

 a single follicle arises from each flower, and in the Australian "Wooden Pear" 

 (Xylomelihm pijriforme, fig. 325 ~), belonging to this order, the huge and extraordi- 

 narily thickened follicle splits completely down the ventral and halfway down the 

 dorsal suture. In Banksia, also, of which a head with fruits is shown in fig. 324, 

 the follicles are very hard and woody. 



