keys to the vascular plants of east texas - Botanical Research ...

476 ASPARAGACEAE/ASPARAGUS
phyletic family of two genera in the order Asparagales, closely related to the Convallariaceae
(Rudall et al. 1997; Fay et al. 2000). As such, it is more closely related to other Asparagales families
such as the Iridaceae and Orchidaceae than it is to many other taxa often put in a broadly defined
Liliaceae (Chase et al. 1995a, 1995b, 1996, 2000; Fay et al. 2000). For a detailed discussion of the
groups formerly treated as Liliaceae in the broad sense, see the family synopsis of the Liliaceae
(here treated in a restricted sense) on page 726. In contrast to the narrow treatment here, the Angiosperm
Phylogeny Group (APG II 2003), based largely on molecular data, recently suggested
treating the Asparagaceae extremely broadly to include a number of diverse families, including
the Agavaceae, Hyacinthaceae, Ruscaceae (including Convallariaceae, Dracaenaceae, and
Nolinaceae), and Themidaceae, among others. As such, the Asparagaceae is extremely broadly
defined morphologically. Because of this lack of morphological coherence, and until nomenclature
in the petaloid monocots is more settled, we are following Judd (2001) in recognizing the family in
the narrow sense. (subclass Liliidae—Cronquist; order Asparagales—APG II)
FAMILY RECOGNITION IN THE FIELD: the only species occurring in East TX is an introduced perennial
1–2(–3) m tall with leaves reduced to scales and numerous very finely dissected leaf-like
branches; flowers are small and axillary and fruits are red berries.
REFERENCES: El-Gazzar & Badawi 1974; Malcomber & Demissew 1993; Hernández 1995;
Kubitzki & Rudall 1998; Rudall et al. 1998b; Judd 2001.
ASPARAGUS L. ASPARAGUS, ASPARAGUS-FERN
AA widely distributed Old World genus of ca. 300 species characteristic of regions with arid
to Mediterranean climates (Judd 2001); some authorities (e.g., Straley & Utech 2002a) are less
sure of the number of species, estimating 170–300. Segregates (e.g., Myrsiphyllum,
Protasparagus) have sometimes been proposed, but these are now generally not accepted
(Malcomber & Demissew 1993; Judd 2001). Based on embryological and molecular evidence,
the genus appears monophyletic (Straley & Utech 2002a). Adaptations to dry conditions are
common, including underground organs to store water and nutrients, leaves reduced to scales,
and the presence of phylloclades (Kubitzki & Rudall 1998). While there is controversy over
their exact anatomical origin (Cooney-Sovetts & Sattler 1986; Kubitzki & Rudall 1998; Judd
2001), the phylloclades (also called cladodes or cladophylls) of Asparagus are generally considered
to be portions of a stem highly modified to have the general form and function of a leaf.
The true nature of these structures can apparently be surmised since flowers are sometimes
borne on the phylloclades. Several species are cultivated as vegetables, for example, the strong
spring shoots of the commonly eaten ASPARAGUS. Others are used as ornamentals (e.g., ASPARA-
GUS-FERN, A. setaceus (Kunth) Jessop, and SPRENGER ASPARAGUS, A. aethiopicus L.), some have
molluscicidal steroid saponins (Mabberley 1997), and a number are used medicinally (Judd
2001). Asparagus aethiopicus, also known as ASPARAGUS-FERN, EMERALD-FERN, or EMERALD-
FEATHER, is a native of c and s Africa. This species, which has gone under various names (e.g., A.
densiflorus (Kunth) Jessop, misapplied) (Judd 2001), is the most commonly cultivated member
of the genus and is well known for “its graceful, airy masses of ‘foliage’ in pots, urns, hanging
baskets, and window boxes” (Bailey & Bailey 1976). The berries of Asparagus species are dispersed
by birds (Judd et al. 2002). (Greek: asparasso, to rip, in reference to the spiny leaves of
some species—Straley & Utech 2002a, or alternatively, the ancient Greek name from, asparagos,
a sprout or shoot, in reference to the food use of the tender sprouts—Shosteck 1974)
REFERENCES: Nichols 1990; Straley & Utech 2002a.
Asparagus officinalis L., (sold in shops, applies to medicinal, edible, and otherwise useful plants),
GARDEN ASPARAGUS, COMMON ASPARAGUS. Rhizomatous, dioecious, glabrous perennial usually
1–2(–3) m tall, unarmed; stems annual, with many very finely dissected, photosynthetic
branches (phylloclades/cladophylls) functioning like leaves; phylloclades needle-like, usually
0.6–2 cm long; leaves reduced to scales ca. 3–4 mm long; flowers axillary, 1–2(–3) per axil, on