VII THE HAWAIIAN STRAND-FLORA 59 



It is possible that the hairy seeds of Gossypium tomentosum 

 may have been thus distributed ; but there is much that is 

 enigmatical about this plant (see Chapter XXVI). 



The Inland Extension of the Beach Plants of 

 Hawail — When we regard the inland extension of littoral plants 

 in Hawaii, we get fresh indications of the meagreness of the strand- 

 flora. Several of the species, as Caesalpinia Bonducella, Cassytha 

 filiformis, Tephrosia piscatoria, &c., show themselves only occasion- 

 ally on the sandy beaches, though they are common enough on the 

 old scantily vegetated lava-flows near the coast and are often found 

 miles inland. Indeed, Dr. Hillebrand not infrequently in describing 

 the station only gives prominence to the situation of the plants 

 away from, the beaches, and places most of them on the old lava 

 plains that extend inland from the coast. It is only by a detailed 

 examination of extensive coast lines in these islands that I have 

 succeeded in preserving to a small degree their reputation as 

 beach plants. A few of them behave somewhat strangely in their 

 inland station. Thus, the seeds of Caesalpinia Bonducella obtained 

 from various localities showed no buoyancy in my experiments ; 

 and had I not found a solitary buoyant seed in the stranded drift 

 I should have inferred that this was a rule without exception. 



It is to be remarked that whilst some plants like Scaevola 

 Koenigii occasionally stray a few hundred yards inland on the 

 surface of the old lava-flows, others like Ipomea pes caprae and 

 Vitex trifolia, that are spread far and wide over the inland plains 

 of Fiji, are confined in Hawaii to the beaches and their immediate 

 vicinity. Some of the plants like Hibiscus tiliaceus, Morinda 

 citrifolia, and Pandanus odoratissimus, that are regarded as having 

 been introduced by the aborigines, behave exactly like indigenous 

 plants in the inland plains ; but this is not necessarily an indication 

 of an indigenous plant in this group, since the Cactus (Opuntia- Tuna) 

 and the Castor-Oil Plant (Ricinus communis) have spread all over 

 the drier lower regions of the islands, whilst Aleurites moluccana, 

 the Candle-Nut Tree, which has no means of reaching these islands 

 without man's agency, now forms entire woods on the mountain 

 slopes, usurping the place often of the original forests. . . . Further 

 details relating to this subject are given in Note 31. 



The principal points in the foregoing discussion of the strand- 

 flora of Hawaii may be thus summed up : — 



(i) The indigenous, that is, the pre-aboriginal, strand-flora of 

 this group lacks not only the mangroves and their associated 

 plants, but also most of the characteristic beach-trees of the South 



