MISCELLANEOUS PLANTS 



221 



in the Florida sand-keys it grows with other littoral plants away 

 from the beach. In the Turks Islands it thrives on both rocky and 

 sandy slopes behind the beach. Dr. Millspaugh, in his paper on the 

 Florida sand-keys, refers to its " often high location on many rocky 

 Antillean islands." In another paper (Plantce Utowance) he alludes 

 to it as growing over low bushes on the shores of Cayman Brae. 



The same American botanist shows that this plant, which is 

 referred to under the synonym of Calonyciion album (House), grew 

 always towards the centre of the sandy interior of the low islets 

 forming the Florida sand-keys, removed alike from the mangrove 

 border on the lee side and the beach on the weather side. Of 

 nineteen islets examined, it was only found on four. 



It was only observed by me on three of the ten islands of the 

 Turks Group, but never on the largest islands. On Gibbs Cay it 

 grew in quantity over the sandy slopes and summit at a height of 

 thirty to sixty feet above the sea, but not on the beach. On Pear 

 Cay, where there is but little beach, it occupied much of the rocky 

 surface, twenty to thirty-five feet above the sea. On Eastern Cay 

 it did not grow on the extensive low sandy flats bordering the sea, 

 but on its stony slopes fifty to sixty feet above the sea-level. 



The seeds are well suited for dispersal by currents. Of ten placed 

 in sea- water in the Turks Islands all were afloat after forty-five days, 

 the kernels being sound and quite dry. In a later experiment in 

 England on seeds that had been gathered for fifteen months, 90 per 

 cent, remained afloat after ten weeks, and from their condition they 

 would evidently have floated unharmed for a considerably longer 

 period. 



Laguncularia racemosa, G. 



This West African mangrove tree, which finds its most character- 

 istic station, with Avicennia nitida, on the landward side of the 

 mangrove swamp, is generally distributed in the West Indies, and 

 has accompanied the other two mangroves, Rhizophora mangle and 

 Avicennia nitida, in their extension to the Bermudas. It grows on 

 the Atlantic side of the American mainland from Florida by way of 

 Mexico and Venezuela to Rio de Janeiro (Schimper, p. 66), and also 

 on the Pacific side on the Panama, Ecuadorian and Lower Californian 

 coasts (Harshberger). 



The tree is dealt with in my book on Plant Dispersal, and here I 

 will chiefly endeavour to supplement those remarks. It will be 

 unnecessary to name the localities in which I noticed it, since it came 

 under my notice wherever I examined the mangrove formation, as 

 in Jamaica, Turks Islands, St. Croix, Grenada, Tobago, Trinidad, 

 Colon, and Panama. According to Millspaugh it grows on ten of the 

 fourteen Florida sand-keys that support mangroves, and is evidently 

 one of the first plants to stock the emerging islet. 



Laguncularia racemosa is as a rule merely semi- viviparous. Only 

 in rare instances does one find the radicle protruding from the fruit 

 on the tree. Generally the dark green embryo does not effect more 

 on the plant than the rupture of the thin seed-coats, the protrusion 

 of the hypocotyl taking place shortly after the fruit has dropped 



