OF INDIA AND CEYLON. 
197 
specimens of this plant be examined, it will be found that 
all kinds of stigmas occur, down to the almost subulate ones 
that occur in other species, such asH. lichenoides. Hydro- 
bryum olivaceum. Tub, has a fiat lichen-like thallus when 
mature, but when young has an erect primary axis ; the 
latter has been described as Podostemon Gardner!, Harv., 
and again as Dicræa apicata, Tal. Other instances could be 
quoted, but these will suffice. The primary di vision of the 
order into sub-orders and tribes is the easiest. Omitting the 
Hydrostachyaceæ as forming a separate order, the family 
separates naturally into two main groups, the Chlamydeæ 
and Achlamydeæ of Tulasne, distinguished mainly by the 
presence or absence of perianth. The former may be again 
separated into two small groups, the trimerous Tristicheæ 
and the pentamerous Weddellineæ. The latter may be 
arranged in a series of groups of increasing zygomorphism 
of flowers. Tulasne simply divides them according to the 
fruits into Isolobeæ or Eulacideæ and Anisolobeæ or 
Podostemoneæ. Weddell divides them into Mourereæ (sta- 
men whorl complete) and Neolacideæ (incomplete whorl), and 
Bentham and Hooker adopt practically the same grouping, 
adding Weddellina to the Mourereæ. Warming in the 
“Naturl. Pflanzenfamilien ” makes three groups, Mara- 
threæ, Mourereæ, Eupodostemeæ, the last being the 
most zygomorphic in the flowers, but including isolobous 
and anisolobous fruits, and being further divided on this 
character into two smaller groups. In his recent paper 
already quoted, he divides the group into Apinagieæ, 
Mourereæ, Marathreæ, and Eupodostemeæ or Podostemeæ, 
sections of gradually increasing zygomorphism. We may, I 
think, regard this as the nearest approach at present possible 
to a natural grouping, but we must acquire a much more 
detailed knowledge of the order before we can draw up a 
good classification. 
All the Asiatic species known belong to the Tristicheæ 
and Eupodostemeæ, and thus split into two widely separated 
groups. 
( 27 ) 
