v Geology and Natural History. 245 



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£1 



8. Plantes a Foicrmis. — Under this title M. Levier has repro- 

 duced in the French language, in the Archive*- Italiennes cle 

 Ftiologie, the substance of Beccari's Pianti Ospitatrici, ossia 

 Piante Formicarie delta Malesia e delta Papusia, (that of the in- 

 troductory portion), from the second volume of Beccari's Malesia. 

 The first part of this, with its copious figures, is devoted to the 

 consideration of plants which hospitably shelter and in part feed 

 colonies of ants in a peculiar and quasi-pathological growth. The 

 first-known plant of this kind is Acacia cornigera of Central 

 America. Hernandez, about the middle of the seventeenth century, 

 described the huge stipular thorns of this tree and the way in 

 which ants of a particular species eat into them from the apex, 

 feed upon the pulpy interior substance, and make there their 

 dwelling, feeding also upon the sweet secretion of the leaf -glands. 

 As Belt (The Naturalist in Nicaragua) describes, the stipular 

 thorns or horns, thus inhabited, grow still larger and in a differ- 

 ent shape from those of the species which are unoccupied; and 

 the ants are said to pay for their food and lodging by effectually 

 keeping off herbivorous animals and other species of insects which 

 otherwise would attack the tree. The ant-inhabited plants next 

 made known were two woody Pxtbiacew, of Sumatra, a Hydnophy- 

 tum and a Myrmecodia, which, in 1750, Rumphius described and 

 illustrated, the first as Nidus formicarum niger, being inhabited 

 by a kind of black ant, the second as Nidus formicarum ruber, 

 because it harbored a red ant. Both shrubs are epiphytic, and 

 both make a large tuber-like growth at the base where the 

 attachment to the foster-tree takes place; — an abnormal and 

 pathological growth, in the sense that the development is stimu- 

 lated and aggrandized by the irritation of the colonizing ants 

 which find food and lodging in the cavernous interior, yet natural 

 because the tuberous enlargement begins in the germination of 

 the plant before the ants attack it. It is the caulicle, or hypo- 

 cotyledonous stem, which thus swells out when the embi'yo ger- 

 minates, and this appears to form the whole of the large tuber. 

 All this is beautifully illustrated by Beccari, in plates 8, 13, and 

 21 of the second volume of Malesia; where it is moreover shown 

 that the swelling caulicle becomes hollow by its own growth. 

 So it appears that these insect-colonized Rubiacea? prepare in 

 advance for their peculiar guests, although the amplitude of the 

 lodging is doubtless increased by their subsequent action. In- 

 deed Beccari states that the seedling plants which fail to be 

 inhabited soon cease to grow. This, however, contradicts the 



