686 Part IV. Chapter 7. 
rest, St. Croix. Looking at the vegetation of St. Croix and the Virgin islands 
in its generality, and without entering into details, we may consider it to be 
identic, as a whole, showing the same main features. Our knowledge of the 
flora of these islands is due to the labors of several botanists '). 
On the sandy shore and on the dunes consisting of innumerable pieces 
of broken shells and corals is found a luxuriant flora, which remains green 
throughout the year, even in dry spells, because of the underground water 
which filters down from the hills above. The species which inhabit the strip 
of upper beach form an Ipomoea pes-caprae Association. The vege- 
tation ‚is in general sparse, the patches of plants being separated by bare 
stretches of sandy beach. Directly behind the upper beach, the botanist finds 
an association of trees and shrubs which correspond to the Barringtonia 
Formation in Java. The trees of this Coccoloba-Hippomane Associa- 
tion are Aıppomane mancinella, Coccoloba uvifera, Chrysobolanus icaco (more 
rare), Thespesia populnea, Terminalia catappa with Caesalpinia (Guilandina) 
bonduc and C. bonducella in the shade of the dominant trees. 
The species of the rocky cliffs are mostly shrubs of low growth with 
thick and coriaceous leaves that are able to resist the force ofthe wind. The 
most common plants of such situations, according to BOERGESEN and PAULSEN, 
are Zanthoxylum spinifex, Erithalis fruticosa, Facguina armillaris, Borrichia 
arborescens and Conocarpus erectus (a mangrove swamp plant here under 
different edaphic surroundings) and, according to EGGERS, Plumeria alba, Cocco- 
loba punctata, Elaeodendron xylocarpum and such herbaceous species as Sieno- 
Zaphrum americanum, Paspalum distichum, Sesuvium portulacastrum and Eu- 
Phorbia buxifolia. A tree also characteristic of rocky shores is Baccharis 
dioica, while on the rocky coasts of St. Thomas and St. John occur many 
succulent plants: Agave Morrisü, Cereus floccosus, Opuntia tuna, O. humilis 
and a species of Thrinax. 
Mangrove Formation. As before mentioned, the mangrove vegetation in- 
habits the bays and the lagoons along shore, as well, as the salt ponds of 
the interior. In many situations Rhizophora mangle is the sole constituent, 
forming a dense forest growth with interlacing branches above, where beneath 
the shade thus found are associated Herpestis Monniera and Acrostichum au- 
EGGERS, BARON H. F.: The Flora of St. Croix and the Virgin Islands. Bulletin 13 United 
States National Museum 1879; BOERGESEN, F. & PAULSENn, OvE: La Vegetation des Antilles 
Danoises. Revue Gen@rale de Botanique Tome XII: 1—108; BOERGESEN, F. & ULDALL, F. P.: 
Vore Vest indiske &er. 1900; MiLLspAuGH, CH. F.: Flora of the Island of St. Croix. Field Co- 
lumbian Museum. Botanical Series Publication 68. Vol. I. No. 7. November 1902; BOERGESEN, F.: 
rer et and systematic account of the Caulerpas of the Danish West Indies. Mem. Acad. 
oy 
‚ Sei. Lett. de Danemark 7me. Ser. Sect. des Sci. A. IV No. 5. 1907; Vegetationen i 
Dansk Westindien; Abstract from Atlanten 1909: 601—632; Notes on the shore Vegetation of 
the Danish West Indian Islands. Botanisk Tidsskrift XXIX 201—259. — BOLDINGH, I: The Flora 
