Family 18. ROSACEAE 
By PER AXEI, RYDBERG 
Herbs, shrubs, or trees, of various habit. Leaves usually alternate, simple, 
often pinnately or digitately dissected, or compound ; stipules usually present, 
sometimes conspicuous. Flowers usually perfect, rarely dioecious or monoe- 
cious, solitary or in spikes, racemes, corymbs, panicles or irregular cymes. 
Hypanthium more or less developed, from flat or saucer-shaped to deeply cam- 
panulate, urn-shaped or almost salver-shaped, often margined with a more or 
less developed glandular annular disk, which bears the stamens. ‘Sepals nor- 
mally 5, rarely 4 or 6-9, often subtended with a set of as many similar organs, 
usually called bractlets. Petals as many as the sepals or wanting; androe- 
cium of l1-many stamens; most commonly these are 20 in three series; one 
series of 5, opposite the sepals, another also of 5, opposite the petals, and a 
series of 10, two placed outside each of the latter; sometimes one or more 
of these series is lacking or reduced or increased in number, or all the stamens 
arranged in a single series on the more developed disk; filaments distinct, or 
rarely slightly united at the base; anthers 2-celled. Gynoecium of 1-many, 
usually wholly distinct pistils; ovaries 1-celled; styles terminal, lateral or 
basal; ovules 1-few. Fruit of achenes, follicles or drupelets, sometimes raised 
on an accrescent receptacle. Endosperm usually wanting or scant, but more 
copious in Opulaster, the tribe Sorbarieae, etc.; embryo usually straight with 
plane cotyledons (except in Osmaronia). 
A. Fruit consisting of 1-5 dehiscent follicles. 
Seeds not winged. 
Carpels alternate with the sepals, or less in number ; stipules none or deciduous. 
Carpels 1-5, if more than one more or less united below; seeds shining, pear-shaped, 
with a bony coat; endosperm present. Tribe 1. NEILLIEAE. 
Carpels usually 5, distinct; seeds dull, linear or linear- 
lanceolate, with a thin coat; endosperm lacking. Tribe 2. SPIRAEEAE. 
Carpels opposite to the sepals; stipules present, persistent. Tribe 3. SORBARIEAE. 
Seeds winged; carpels in ours more or less united; stipules 
deciduous. Tribe 4, QUILLAJEAE. 
B, Fruit consisting of indehiscent achenes or drupelets. 
I. Carpels not enclosed in a fleshy hypanthium. 
a. Fruits consisting of dry achenes. 
1. Ovules 2, one above the other ; achenes usually 1-seeded 
and more or less flattened, arranged in a single circle. 
Hypanthium hemispheric ; anthers cordate at the base, 
more qr less didymous ; filaments filiform or subulate ; 
shrubs with simple leaves. Tribe 5. HOLODISCEAE. 
Hypanthium flat or nearly so; anthers nearly globose, 
acute at the base; filaments subclavate; perennial 
herbs with pinnately dissected leaves. Tribe 6. ULMARIEAE. 
2. Ovules and seeds solitary ; achenes usually turgid and if 
many spirally arranged. 
a. Seeds inserted at the distal end of the ovary, 7. ¢., at 
the point where the style arises, pendulous or in 
genera with basal styles ascending ; radicle superior. 
Dise at the mouth of the hypanthium annular or ob- 
solete ; leaves and branches alternate. 
Style articulated to the ovary ; hypanthium from 
campanulate to almost flat, neither contracted at 
the throat nor closely investing the achenes ; ; 
flowers cymose or solitary. Tribe 7, POTENTILLEAE. pat : 
VoLUME 22, Part 3, 1908] 239 
