KEY TO SUB-CLASSES, OKDERS AND GENERA. 117 
KEY 
TO THE 
CHIEF SUB-DIVISIONS, ORDERS AND GENERA 
ADAPTED CHIEFLY FROM 
SIR D. BRANDIS’ INDIAN TREES AND SIR D. PRAIN’S 
BENGAL PLANTS. 
KEY TO THE CHIEF SUB-DIVISIONS. 
I, Plants bearing flowers with stamens or pistils or both ; pistils bearing 
ovules that may ultimately change into embryonate seeds :— .-- PHANEROGAMIA, 
(i) Pistils with a stigma ; ovules contained in an ovary composed of a carpel 
with cohering edges or of two or more cohering carpels :— ... ANGIOSPERMEX. 
(1) First leaves of embryo two and opposite; framework of leaves 
usually of netted veins; perianth usually 4-merous or, more often, 5-merous; 
wocdy substance of stems usually in rings of bundles round a central pith :— 
DicoTyLEDONEs. 
(A) Corolla usually and calyx almost always present; flowers gen- 
erally hermaphrodite :-— 
(a) Segments of corolla almost always free, frequently some or all 
of them absent; stamens often indefinite :-— 
(a) Stamens hypogynons arising apart from calyx direct from the 
receptacle or from a disk that crowns the pedicel; seg- 
ments of calyx usually free:— | = THALAMIFLORY, 
(8) Stamans epigynous or perigynous arising from calyx or from 
a disk lining its tube; segments of calyx usually united :-— 
CALYCIFLORA#. 
(b) Segments of corolla almost always, and of calyx very often, 
coherent, corolla rarely absent; stamens almost always 
definite, usually adherent to corolla, sometimes hypogynous, 
rarely epigynous ; ovary inferior, or if ee the carpels 
not more than 3 :— ... COROLLIFLOR#, 
(B) Corolla almost always and calyx often absent ; flowers generally 
l-sexual:— ... ae ons vee aes .. INCOMPLETZ. 
(2) First leaves of embryo Peo or alternate ; framework of leaves of 
parallel-longitudinal, or less often parallel-divergent, rarely netted, veins; 
perianth usually 3-merous; woody substance of the stem in isolated 
bundles :— a MONOCOTYLEDONES, 
(ii) Pistils without a stigma ; ovules borne on an ovary composed of an 
open carpel; perianth almost always absent ; first leaves of embryo two and 
opposite or more than two and whorled ; woody substance of stem in rings of 
bundles round a central pith:— _ ... ae soa GYMNOSPERMA. 
If. Plants without flowers, bearing antheridia or : archogonia or both on 
minute prothalli in one stage of existence, and bearing small sporangia con- 
taining minute spores in an alternating stage :— +. PTERIDOPHYTA, 
(i) Leaves large in proportion to stem, the fertile ones “not confined toa 
particular region :— 
(1) Leaves bearing sporangia on their lower surfaces:— _... «. FILices, 
(2) Leaves bearing sporangia on their upper surfaces :— ... RHIZOCARPER, 
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