Notes. 
597 
logues of a three-lobed segment of the carpel. In the normal ovule 
the upper surface of the inner integument is directed inwards to the 
nucellus, this latter being morphologically an emergence from that sur- 
face, while the upper surface of the outer integument is directed out- 
wards and away from the inner integument. This applies to all cases : 
Brongniart, Warming, Cramer, Celakovskf. 
Gnetaceae. 
Gnetum has normally three envelopes surrounding the nucellus. 
Theories as to their nature : — 
Some regard outer integument as an ovary, others as a perianth, 
others again as a third integument. View maintained here that it is 
a perianth, as two integuments occur uniformly throughout Gymno- 
sperms. 
Ephedra and Welwitschia each possess two integuments. Theory 
as to nature of outer envelope in former : perianth. 
Coniferae. 
Views as to nature of the sporangial appurtenances : — 
Baillon, Parlatore, Sperk, and others regarded the single envelope 
as the ovary ; almost all other botanists agree as to its integumental 
nature. Seminiferous scale : Schleiden, Baillon, Strasburger, Masters, 
regard it as an axial structure ; Sachs and Eichler as a ligular placenta ; 
Delpino and Penzig as the two lateral lobes of the bract ; R. Brown as 
a carpel ; Van Tieghem as the first and only leaf of an axillary bud ; 
Braun, Caspary, Von Mohl, Stenzel, Celakovskji, and several others 
as homologous with the two first leaves {or their ovular representatives ) 
of an axillary bud. Celakovsk^ holds further that throughout Coniferae 
the ovule has two integuments; in Abietineae, Taxodineae, Cupressineae, 
Araucarieae, the outer integument is normally proliferated as a semini- 
ferous scale, this being the exact counterpart of certain stages in the 
abnormal proliferation of the ovule of Angiosperms ; in Podocarpus , 
Cephalotaxus , Torreya and Ginkgo it is the outer fleshy coat of the 
seed ; in Taxus, Microcachrys, Dacrydium, it is the fleshy aril. 
Cycadaceae. 
Most authors regard ovule as possessing a single integument. Cela- 
kovsk/ considers it, along with Cephalotaxus , &c., as being holochla - 
mydeous , i.e., having the two integuments intimately united, the outer 
fleshy and the inner woody. 
