184 KEY TO SUB-CLASSES, ORDERS AND GENERA: 
CIY—MORACE Ai—cont. 
(2) Leaves penninerved :— 
(A) Flowers dioecious, males in cylindric spikes, females in subglobose 
heads, inflorescence solitary in axils :— dccelxxi—Chlorophora. 
(B) Flowers moncecions, 1-sexual, densely ‘crowded on subglobose 
receptacles:— ... .« deccelsxvii—Artocarpus 
CV—URTICACEA— 
[Anatomical featwres.—Bast fibres strongly developed in the bark, often very 
long. Cystolith cells conspicuous in the epidermis. No laticiferous tubes. Stinging 
hairs in some genera. | 
(I) Chimbers ; flowers dioecious, males in axillary panicles, female in pairs in 
the axils of the broad bracts of a catkin-like evoid spike; leaves opposite, 3—5- 
costate, upper entire, lower lobed :— as “3 ... decelxxvii (bis)—Humulnus, 
(II) Trees and Shrubs :-— 
(i) Leaves and stems with stinging hairs; leaves alternate, mostly 3- 
costate , flowers cymose, 2—5-merous :— 
‘Q) Female perianth of 4 sepals :— ay ... decclxxviii--Laportea. 
(2) Female perianth tubular, 2—3- couthed : = ... deeclxxix—Girardinia. 
(ii) Leaves and stems without stinging hairs :— 
(1) Inflorescence, cymose in the male, on a fleshy receptacle in the 
female; perianth female 3——&-partite; leaves alternate, 3- costate; 
epiphytic :— ae eae ... decclxxx—Procris. 
(2) Inflorescence ‘spicate, fasicled, ~ racemed, or panicled, clusters ; 
perianth of female tubular, ot male 2—5-merous :— 
(A) Fruitiog heads dry ; stigma filiform :—— 
(a) Stigma persistent ; leaves alternate or opposite, 3-costate :— 
decclxxxi—Be hmeria. 
(b) Stigma deciduous ; leaves alternate, opposite, or 3-whorled, 3- 
costate :— Boe decclxxxii—Pouzolzia. 
(B) Fruiting heads succulent ; “perianth ovoid with minute mouth ; 
leaves alternate, 3--5-costate :— 
(a) Leaves green beneath, tertiary nerves not prominent :— 
decelxxxiii— Villebrunia. 
(b) Leaves white or green beneath, tertiary nerves prominent :—- 
accclxxxiy—Debregeasia 
CVI—PLATANACEA— 
(I) Characters of the order (q.v. in the Synopsis)— ... decclxxxv—Platanus, 
CVI (bis) —MYRICACEA— 
(1) Characters of the order (q.y, in the Synopsis)— decclxxxv (bis).— Myrica. 
CVII—CASUARINACEA— 
(I) Characters of the order (q.v. in the Synopsis) — .. dcecclxxxvi—Casuarina. 
CVIII—BETULACEZ.— 
[Anatomical featwres—Most species of Alnus, Carpinus, and Corylus have, 
besides the fine medullary rays, others which may be called compound rays, 
consisting of a number cf fine, sometimes broader, rays alternating with elongated 
parenchyma cells and wood fibres. These compound rays run through the ordinary 
tissue which is traversed by vessels. The wood fibres asa rule have bordered pits. } 
(I) Stamens 4—12 on each bract, more or less distinctly arranged in 3 flowers, 
each with a perianth of 2—4 leaves ; anther cells without tufts of hair; ovary 
without perianth :-— 
(i) Anther cells distinct ; scales of female spike thin, deciduous :-— 
decelxxxvii— Betula, 
(ii) Anther cells distinct cr connate ; scales of female spike persisent, and 
woody in fruit :— .. dcecelxxxviii-—Alnus, 
(II) One 3—6-androus flower on n each bract without perianth in male; 
anther cells with a tuft of hairs ; perianth thin in female, adnate to ovary :— 
