FEBRUARY 15, 1901.] 
bils are quickly killed by desiccation and 
freezing temperatures. 
Seedlings of Arisema: PRrorrssor D. T. Mac- 
Dovgat, New York Botanical Garden. 
The seedlings of Arisema Dracontium gen- 
erally do not develop the plumule. The 
cotyledon pushes down into the soil carry- 
ing the hypocotyl, the base of which en- 
larges to form a bulb, in which is stored the. 
reserve material withdrawn from the seed 
and not used. In a few instances, how- 
ever, a single small leaf is developed; 
usually this does not take place until the 
second season of activity or the third season 
of existence of the seed. Similar sapro- 
phytism is exhibited by the seedlings of 
Arum maculatum which never develop the 
plumule until the second year of growth. 
The Insular Flora of Mississippi and, Louisiana : 
Proressok Francis E. Luoyp, Teachers 
College, and Proressor S. M. Tracy, 
Biloxi, Miss. 
The paper deals with the climate, physi- 
ography and thevegetation of the Mississippi 
Sound Islands and Delta, and is especially 
concerned with a comparison of the ecolog- 
ical conditions in this region and that re- 
cently studied by Kearney, namely, Ocra- 
eoke. The results show for the former a 
longer growing season, more favorable wind 
conditions and a greater amount of sun- 
shine. 
The islands of the Delta region are of 
three kinds, the sand islands, the muck- 
marsh islands and the mud-lumps. 
These islands have a strand vegetation 
of which four formations are recognizable, 
viz., the beach, sand plain, dune and salt 
marsh formations. 
The beach formation contains succulent 
annuals of a halophytic character such as 
Sueda linearis, Salsola kali and Sesuwviwm portu- 
lacastrum, and in its upper zone some trop- 
ical strand plants such as [pomea pes-capre, 
T. acetosefolia (two prostrate leaf-succulent 
SCIENCE. 
253 
morning-glories), and rarely Canavalia ob- 
tusefolia. The back beach plants are chiefly 
grasses, of which Panicwm amarum, common 
along the north Atlantic Coast, and Uniola 
paniculata, a more southern strand ee are 
the leading elements. 
The sand plain contains saeealont peren- 
nials as well as annuals, of prostrate and 
cespitose habit. The most striking plants 
of the sand plain are Iva imbricata and 
Serenoa serrulata, a prostrate palmetto, both 
of which build a pedestal dune. 
The dune formation has two leading 
associations. One of these is the thicket 
(Ilex-Myrica) association inhabiting small 
established dunes which support a plentiful 
herbaceous undergrowth. The larger dunes 
are inhabited by Serenoa serrulata, Khus 
copalina and several grasses. These dunes 
may attain a height of twenty meters and 
in their leaward march may bury the trees 
in their path. 
The salt-marsh associations of chief in- 
terest are those of the muck-marshes. Two 
such are to be seen, namely the Batis-Sali- 
cornia association composed of leaf and 
stem succulents, and the grass association 
of which Spartina (two species) is the lead- 
ing type. Onthe muck-marsh is sometimes 
superposed a water-moved shell dune com- 
posed of shell fragments and supporting a 
vegetation of annual and perennial plants 
of less marked halophytic character. 
Some Problems connected with Fertilization in 
Plants: Lecture by Proressor G. F. At- 
Krnson, Cornell University. (Illustrated 
by stereopticon.) 
Professor Atkinson discussed recent ad- 
vances which have been made in the study 
of fertilization in plants and their signifi- 
cance, and pointed out the problems still 
awaiting solution. 
The Morphology of the Fruit of Opuntia: PRro- 
FEssoR J. W. Toumry, Yale University. 
(By invitation. ) ; 
