462 FRUITS REPLACED BY OFFSHOOTS. 



that in the regions where Lilium bulhiferum grows those insects are wanting 

 which should convey its pollen from flower to flower. As the Orange Lily possesses 

 no arrangements for autogamy, no fruits are formed in the absence of insect-visits. 

 It appears that this plant has lost the capacity for autogamy ; at any rate if a stigma 

 be pollinated with pollen from the same flower, on plants in a garden, no result 

 follows. On the other hand, oflshoots in the form of numerous bulbils are pro- 

 duced by Lilium bulbiferum, by means of which it is propagated and dispersed. 

 In several valleys of the Central Alps it does not flower at all, and thus obviously 

 depends entirely upon its bulbils for propagation. 



Gagea Persica (fig. 348^) a member of the Liliaceae, repeats several of the 

 peculiarities met with in the Orange Lilies. The stem of this little bulbous plant 

 terminates in a flower which, in the absence of insect-visits, withers without 

 setting fruit. Little buds arise in the axils of its filamentous foliage-leaves. With 

 the atrophy of its fruits these grow into little bulbils (fig. 343'^); but if fruit be 

 formed these buds for the most part atrophy. Nor must we omit to mention the 

 ally of this plant, Gagea Bohemica, belonging to the flora of Central Europe. 

 From its specific name, Bohemica, it might be supposed that it is solely met with 

 in Bohemia; this is not so, it was first discovered there, but is distributed widely 

 over Persia, Asia Minor, Southern Russia, and the Balkan Peninsula. Further west 

 Gagea Bohem^ica occurs rather sparingly, in Bohemia and in the neighbourhood of 

 Magdeburg — these occasional occurrences being no doubt a last lingering remnant 

 of a Steppe-flora which at some former period extended to the Harz Mountains. 

 We shall later have opportunity of explaining how this Steppe-flora has retreated 

 eastwards and been replaced by other communities of plants; here we may mention 

 that this retreat of the Steppe-flora was accompanied by a retreat of the Steppe- 

 fauna. The Steppe-antelope, Steppe-marmot, Steppe-porcupine, rat-hare, &c., which 

 existed in those times in Central Germany, have long forsaken this region, and we 

 have good grounds for assuming that the insects of that period have also migrated. 

 It is certainly remarkable that this Steppe-plant, Gagea Bohem^ica, the flowers of 

 which are adapted to insect-pollination, and in which autogamy does not occur, 

 should never ripen its fruit and seeds in these scattered localities of Bohemia and 

 Germany. One can hardly help supposing that this abortion of fruits is due to 

 the absence of those Steppe-insects which were formerly, in all probability, 

 distributed also over Bohemia and Germany. Whatever be the explanation, it is a 

 fact that these isolated western representatives have never been known to ripen 

 fruit and seed. But instead, at the bases of the leaves, bulbils are formed which 

 fall away and root, maintaining and propagating the species. 



Equally instructive is the case of one of the Chick weeds, Stellaria bulbosa, now 

 confined to a restricted area in Carniola and Croatia. It flourishes there in the deep, 

 black humus of the forest floor, preferably on the banks of little water-courses, 

 forming here and there dense, luxuriant masses. Its flowers unfold quite early in 

 the spring; and although they are fairly conspicuous, standing up white from the 

 ^reen background, they are rarely visited by insects. The few flies which come to 



