106 



JOURNAL OF THE ARNOLD ARBORETUM 



[vol. I 



media Mett.), a spreading, vase-shaped plant with a rosette of bright green 

 leaves. a meter long abounds on the limestone and on trees, but nowhere 

 more so than on Sekimonzan. On this mountain I did collect the endemic 

 Hounds-tongue {Scolopendrium Ikenoi Makino) with its 7 cm. long, cor- 

 date-acuminate, delicate fronds. It is outside the province of this paper 

 to enter further into det^iils regarding the Ferns, but since they are the 

 dominant undergrowth in the forests and everywhere abundant, they are 

 a most important feature of the flora of the Bonin Islands. 



CLIMBERS 



Frevcinetla forinosana Hemsl. 

 Smilax china L. 

 PIl>or futokadsura Sieb. 

 Ck'matis bouiuensLs Ilay. 

 Cassytha filifonuis L. 



Canavalla ubtusifolla DC- 

 Miifuna gigautca DC. 



Vigna rctusa A. Gray 



Colubrina asiatica Brongn. 

 Cissus japonica Willd. 

 Elaraguus rotuiulata Nakai 

 Trachelospernium divaricatum Kanitz 

 Ipomaea biloba L. 

 Argyrcia tiliaefolia Wight 

 Psycholrla serpens var. macropliylhi 

 Koidz. 



There are fifteen climbers as shown above and they l)elong to 12 families 

 and fifteen genera. Of the two JVIonocotyledonous sj>ccies the Smilax is a 

 common jilant, on the larger islands at least, and calls for no special remark. 

 The Frcycinetia on the other hand ranks with tlie Clematis, the Elaeagnus 

 and the Trachelospermum as one of the four principal climbers of the Islands. 

 As before mentioned it forms dense impenetrable thickets on the uj)})er 

 mountain slopes and in the forest scales the highest trees. The sterns put out 

 roots which cling to the moist tree-trunks and rocks. The dark green, spirally 

 arranged leaves are smooth on the margin and flaccid, and the finger-like 

 fruit, in a cluster of three, is red and soft and disappears soon after it is ripe 

 in August. When in Formosa I closely examined the species in the type 

 locality and could find no difference betAveen it and the Bonin plant. The 

 Piper is a widc-si)read species in south Japan, Liukiu, and Formosa and in 

 the Bonins it is common on trees and rocks. Its orange-yellow spicate 

 flowers are quite attractive. The Clematis is allied to the Japanese C. 

 paniculafa Thunb. and is common in thickets and on the margins of forests 

 where it can enjoy the sunlight. The Cassytha is not common and, curi- 

 ously enough, grows on the grassy hilltops and not on the seashore, its 

 normal habitat in Liukiu, Formosa and the other places where I have met 

 with it. Of the three Leguminous genera the Mucuna is rare and is confined 

 to shady forests and thickets. The Canavalia and Mgna are scarcely woody 

 and al)Ound in oj)en grassy places near the sea, and if the site is })rackish 

 and swampy so much the better; both are cosmopolitan in the tropics. 

 The Mucuna is also widely spread, though tliere is a possibility of the Bonin 

 plant with its' pink flowers being a distinct but critical species. The 

 Colubrina, which in growth and ai)pearance strongly suggests Celastrus, I 

 saw on Ilaha-jima in one place only and it is evidently rare. The Cissus I 



did not see and I am indebted to Mr. Otonio for a specimen; it is certainly 



