KEY T) SUB-CLASSES, ORDERS AND GENERA. 151 
XLIV—ROSAC EB Ai—cont, 
(iii) Leaves simple and lobed, or compound ; carpels many, forming an 
etaerio in fruit (fleshy compound drupe) ; ovules 2; thorny climbers :— 
coelxxix—Rubus. 
(Il) Ripe carpels enclosed within the calyx-tube :— 
(}) Carpels many free, but when ripe enclosed in accrescent calyx-tube :— 
ccclxxx—Rosa. 
(ii) Carpels connate, forming a 1—5-celled ovary, more or less adnate to the 
cdlyx-tube which is fleshy in fruit and encloses them :— 
(1) Ovary 5-celled, ovules many in each cell:-- ........ ceclxxxiii--Cydonia, 
(2) Ovary 2—5-celled, ovules 2 in each cell :—- 
(A) Flowers panicled :-- ae ae ... @ccolxxxiv—Hriobotrya. 
(B) Flowers corymbose or fascicled :—- 
(a) Fruit a pome or berry :-- a ay ... ccclxxxy—~Pyrus. 
(b) Fruit 2--3-celled with thin endocarp :— ... cceclxxxvi——Photinia, 
(¢) Fruit a drupe with 1-5 bony stones; leaves cut, toothed or 
serrate :— .. ceccelxxxvii--Crategus. 
(d) Fruit a drupe with 2—4 bony stones ; leaves entire :— 
ecelxxxviii——Cotoneaster. 
XLV--SAXIFRAGACH A—- 
(1) Leaves opposite :— 
(i) Flowers corymbose :— 
(1) Flowers 5-merous ; stamens 10, filaments winged :—— cocexc—Deutzia. 
(2) Flowers 4—§-merous ; petals sometimes falling as in a cap; calyx of 
sterile flowers enlarged and foliaceous in fruit ; stamens S——10, filaments linear or 
subulate :-— Ake We “ns oy Ax bat tee ccclxxxix-— Hydrangea, 
(ii) Flowers axillary or in small terminal cymes, 4-merous, large, fragrant ; 
stamens 20-—40, filaments linear or subulate :-- i S08 ccexci— Philadelphus, 
(II) Leaves alternate :-- 
(i) Petals and stamens attached to cup-like disk, which surmounts the 
ovary ; fruit a capsule ; leaves with resinous dots, not lobed :-—... cccxcii—Escallonia. - 
(ii) Calyx guperior, tube often produced beyond the ovary ; fruita berry ; 
leaves palmately lobed :— 33; oe ioc ves Ase ie cccexcili—Ribes. 
XLVI—HAMAMELIDACE.A,.— 
[Anatomical features._- Wood fibres have bordered pits on their walls resembling 
ConiFER®, and thick walls. Medullary rays are narrow, vessels small, and wood paren- 
chyma of no importance. } 
(I) Leaves palmately 5--7-costate, sometimes 3-cuspidate, stipules large enve- 
loping the buds ; flowers polygamous ; calyx 5-lobed ; petals variable in number, 
linear-spathulate in bisexual, rudimentary in female, flowers ; stamens 10—14, 
filaments long :—- uae ae sae soe vee sae ccexciv—-Bucklandia, 
XLVII--RHIZOPHORACE A - 
[Anatomical fetures.——The littoral species of this, together with trees and shrubs of 
other orders, form the mangrove forests, which have a strikingly peculiar character, 
In the soft mud in whichthey grow, these species are firmly anchored by means of widely- 
spreading and much branching roots, and in many cases by aerial roots descending frum 
the branches. Thus they are protected against being uprooted by storms and by the waves 
during high water. The leaves have a very thick cuticle, and other arrangements for 
diminishing transpiration, and they are full of water storing tissue. Their structure 
resembles that of plants growing in deserts and very dry localities ; and the probable 
explanation is that transpiration is checked in order to prevent an injurious excess of 
sea water salts in the sap which fills their tissue. Mangrove trees and shrubs have 
other peculiar features, such as knees and other excrescences projecting upwards from 
the roots, believed to Jacilitate the access of air to the roots, which are immersed in 
_mud and water; as well as the fact that their seeds often germinate on the tree, making 
considerable growth before they fall into the mud of the tiaal swamp. } 
(1) Ovary inferior or 4 inferior ; leaves coriaceous :— 
(i) Littoral species ; seed germinates on the tree, sending down 4 long 
radicle, albumen O :— 
