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DR JOHN M‘LEAN THOMPSON ON NEW STELA R FACTS, 
ontogeny of a number of higher ferns, in which medulla and inner phloem are early 
secured ; for the Lindsaya structure is a stage in intrastelar amplification from an 
original protostele which may persist into the adult axis, or be passed through to a 
higher stelar state. The Schizaeoid-Dicksonioid affinity of the Lindsay as has been 
indicated by Bower (ll) and others. It will accordingly be of interest to know 
the ontogenetic facts for a plant of like general affinity but more advanced adult 
stelar structure. The facts for Loxsoma Cunninghamii will now be given. 
Loxsoma Cunninghamii. 
The adult solenostele of this species has been fully described by Gwynne- 
Vatjghan (24). The ontogeny opens with a basal region of protostely of varying 
length, and bearing both leaf- and root- 
traces. The bases of text-figs. 6 and 7 show 
the general arrangement of tissues in this 
region ; xylem is solid black, parenchyma is 
white, phloem is hatched, and endodermis is 
an unbroken line ; leaf-traces are lettered, 
and levels referred to are numbered. Fig. 34 
shows the stelar structure at I, text-fig. 6, 
and shows the solid protostely. As leaf- 
trace a is departing a medulla appears. 
At its core is a strand of sieve-tubes. Fig. 
35 shows the stelar structure at this level 
(II) ; there is a xylic gap, but the inner 
(Ph/) and outer phloem (Ph.) are not united 
through it. Fig. 36 shows the structure at 
III ; the xylic gap is closed, and the slender 
core of phloem persists. For a consider- 
able distance leaf-traces are liberated in the 
protostelic manner (b, c, d, and e). The 
pith is well developed, and the central strand 
of phloem is locally indefinite, IV and V. 
At VI it is tubular, and involves parenchy- 
matous cells. Fig. 37 shows the stelar structure during departure of leaf-trace 
d, and illustrates the Lindsaya condition with protostelic departure of a trace. 
At VII there is a second xylic gap independent of a leaf-trace. At this level the 
inner phloem is indefinite, but no indication of a phloic connection through the 
gap is seen. As leaf-trace f is departing, the inner phloem becomes definitely 
tubular. Above f is a xylic gap through which inner and outer phloem are 
linked for the first time. Fig. 38 shows the stelar structure at VIII ; the inner 
phloem (Ph/) is a tube within the parenchymatous pith. The stele is in this 
n 
